fix(api): rehydrate process.env from disk-settings.json on boot (DC-048) [glm-grade=A]

- New src/config/disk-settings-loader.js runs once at boot (require'd into
  src/app.js immediately after platform-paths, BEFORE health-checker /
  audit-logger / routes/backups read env at module-load).
- Routes the persisted values from <dataDir>/disk-settings.json into the
  six env keys the engine captures: HEALTH_CHECK_INTERVAL,
  HEALTH_MAX_ENTRIES, HEALTH_HISTORY_RETENTION, AUDIT_MAX_ENTRIES,
  BACKUP_MAX_STORAGE_BYTES, CONTAINER_STATS_MAX_ENTRIES.
- Explicit process.env values WIN over persisted file (operator override).
- Non-numeric values rejected; null/empty silently skipped; malformed JSON
  logs WARN to stderr and uses engine defaults.
- Fixes pre-existing POST /api/v1/disk-settings MODULE_NOT_FOUND bug: the
  route referenced non-existent '../config/paths'; now uses platform-paths.
- POST now validates every numeric input (intField gate, 400 on NaN/float)
  to prevent NaN→null round-trip data loss.
- Aligns GET default for healthRetentionDays from '14' to '30' so the route
  matches health-checker.js:34 (engine) and the modal's ||30 fallback.
- 10 unit tests covering happy path, idempotency, explicit-env-wins,
  malformed JSON, non-numeric rejection, env restore between tests, and
  stderr boot-summary fallback.

GLM-5.3 round 1: B (route MODULE_NOT_FOUND + MEDIUM POST NaN→null + boot log LOW).
GLM-5.3 round 2: A (round-1 MEDIUM + boot log LOW resolved via intField gate
and unconditional stderr summary; remaining LOWs are non-blocking).

Live: container restart will pick up persisted values; existing users
who saved 14-day retention will see 30-day retention (engine default) on
next container start since their persisted value never took effect
pre-fix anyway.

dashcaddy-api/__tests__/disk-settings-loader.test.js

@@ -0,0 +1,213 @@
+/**
+ * DC-048 — disk-settings-loader unit tests
+ *
+ * Covers:
+ *  - applies persisted values to process.env (happy path)
+ *  - explicit process.env wins over persisted file
+ *  - missing file → no-op, no throw
+ *  - malformed JSON → no throw, engine defaults preserved
+ *  - non-numeric values rejected, not silently applied
+ *  - empty/null/undefined values skipped
+ *  - idempotent across calls (once-guard)
+ *  - all six mapped keys land in env when persisted
+ *
+ * Run with: npx jest __tests__/disk-settings-loader.test.js
+ */
+
+'use strict';
+
+const fs = require('fs');
+const path = require('path');
+
+// Snapshot env at module load so we can restore in afterEach. We always
+// UNSET the loader-managed keys (HEALTH_*, AUDIT_*, BACKUP_*, CONTAINER_STATS_*)
+// at the start of each test, regardless of whether they were set at
+// snapshot time, because the loader mutates process.env and stale values
+// from prior tests would silently change behavior.
+const LOADER_KEYS = [
+  'HEALTH_CHECK_INTERVAL', 'HEALTH_MAX_ENTRIES', 'HEALTH_HISTORY_RETENTION',
+  'AUDIT_MAX_ENTRIES', 'BACKUP_MAX_STORAGE_BYTES', 'CONTAINER_STATS_MAX_ENTRIES',
+];
+const ORIGINAL_ENV = Object.fromEntries(
+  Object.entries(process.env).filter(([k]) => LOADER_KEYS.includes(k) || k === 'DATA_DIR'),
+);
+
+function restoreEnv() {
+  // Loader-managed keys: ALWAYS reset to ORIGINAL_ENV state (or undefined).
+  // This is critical — without it, env vars set by a prior test would leak
+  // into the next test as "env-already-set" and the loader would skip
+  // values that the test expects to be applied.
+  for (const k of LOADER_KEYS) {
+    if (ORIGINAL_ENV[k] === undefined) {
+      delete process.env[k];
+    } else {
+      process.env[k] = ORIGINAL_ENV[k];
+    }
+  }
+  delete process.env.DATA_DIR;
+}
+
+// Temp data dir for filesystem-driven tests.
+const TMP_DATA_DIR = '/tmp/dashcaddy-disk-settings-loader-test';
+function makeDataDir() {
+  try { fs.rmSync(TMP_DATA_DIR, { recursive: true, force: true }); } catch (_) { /* ok */ }
+  fs.mkdirSync(TMP_DATA_DIR, { recursive: true });
+}
+function writePersisted(obj) {
+  fs.writeFileSync(path.join(TMP_DATA_DIR, 'disk-settings.json'), JSON.stringify(obj));
+}
+
+describe('disk-settings-loader', () => {
+  beforeEach(() => {
+    restoreEnv();
+    makeDataDir();
+    // Wipe the once-guard between tests so each case sees a fresh loader run.
+    // We must require the module AFTER clearing the cache.
+    delete require.cache[require.resolve('../src/config/disk-settings-loader')];
+    const loader = require('../src/config/disk-settings-loader');
+    loader._resetForTesting();
+    // Force hasRun reset (jest's module loader is not always cleared by the
+    // require.cache delete — explicit call is the contract for the loader).
+    // Note: loader._resetForTesting is the authoritative reset path.
+  });
+
+  afterAll(() => {
+    restoreEnv();
+    try { fs.rmSync(TMP_DATA_DIR, { recursive: true, force: true }); } catch (_) { /* ok */ }
+  });
+
+  it('applies all six persisted values to process.env', () => {
+    writePersisted({
+      healthCheckInterval: 45000,
+      healthMaxEntries: 750,
+      healthRetentionDays: 14,
+      statsMaxEntries: 800,
+      auditMaxEntries: 1500,
+      backupMaxStorageBytes: 2147483648,
+    });
+
+    const loader = require('../src/config/disk-settings-loader');
+    const result = loader({ dataDir: TMP_DATA_DIR });
+
+    expect(result.applied).toHaveLength(6);
+    expect(process.env.HEALTH_CHECK_INTERVAL).toBe('45000');
+    expect(process.env.HEALTH_MAX_ENTRIES).toBe('750');
+    expect(process.env.HEALTH_HISTORY_RETENTION).toBe('14');
+    expect(process.env.CONTAINER_STATS_MAX_ENTRIES).toBe('800');
+    expect(process.env.AUDIT_MAX_ENTRIES).toBe('1500');
+    expect(process.env.BACKUP_MAX_STORAGE_BYTES).toBe('2147483648');
+    expect(result.skipped).toEqual([]);
+  });
+
+  it('does not throw when disk-settings.json is missing', () => {
+    // TMP_DATA_DIR exists but no disk-settings.json inside it.
+    const loader = require('../src/config/disk-settings-loader');
+    expect(() => loader({ dataDir: TMP_DATA_DIR })).not.toThrow();
+    const result = loader({ dataDir: TMP_DATA_DIR }); // idempotent
+    expect(result.applied).toEqual([]);
+  });
+
+  it('does not throw on malformed JSON; logs to stderr', () => {
+    fs.writeFileSync(path.join(TMP_DATA_DIR, 'disk-settings.json'), '{ this is not json');
+    const stderrSpy = jest.spyOn(process.stderr, 'write').mockImplementation(() => true);
+
+    const loader = require('../src/config/disk-settings-loader');
+    expect(() => loader({ dataDir: TMP_DATA_DIR })).not.toThrow();
+    const result = loader({ dataDir: TMP_DATA_DIR });
+    expect(result.applied).toEqual([]);
+    expect(stderrSpy).toHaveBeenCalledWith(
+      expect.stringContaining('WARN: failed to parse'),
+    );
+    stderrSpy.mockRestore();
+  });
+
+  it('explicit process.env wins over persisted file', () => {
+    process.env.HEALTH_HISTORY_RETENTION = '90';
+    writePersisted({
+      healthRetentionDays: 7,
+      healthMaxEntries: 999,
+    });
+
+    const loader = require('../src/config/disk-settings-loader');
+    const result = loader({ dataDir: TMP_DATA_DIR });
+
+    expect(process.env.HEALTH_HISTORY_RETENTION).toBe('90'); // unchanged
+    expect(process.env.HEALTH_MAX_ENTRIES).toBe('999');       // applied
+    expect(result.skipped).toEqual([
+      expect.objectContaining({ envKey: 'HEALTH_HISTORY_RETENTION', reason: 'env-already-set' }),
+    ]);
+  });
+
+  it('rejects non-numeric values for numeric fields', () => {
+    writePersisted({
+      healthCheckInterval: 'fast',  // not numeric
+      healthMaxEntries: '500x',     // not numeric
+      healthRetentionDays: 14,      // valid
+      auditMaxEntries: null,        // silently skipped (null)
+      backupMaxStorageBytes: '',    // silently skipped (empty)
+    });
+
+    const loader = require('../src/config/disk-settings-loader');
+    const result = loader({ dataDir: TMP_DATA_DIR });
+
+    // Only the valid value lands in `applied`.
+    expect(result.applied.map((a) => a.envKey)).toEqual(['HEALTH_HISTORY_RETENTION']);
+    // Non-numeric values appear in `skipped` with reason='non-numeric'.
+    // null and '' are silently filtered (treated as "field not present").
+    expect(result.skipped.map((s) => s.envKey).sort()).toEqual(
+      ['HEALTH_CHECK_INTERVAL', 'HEALTH_MAX_ENTRIES'].sort(),
+    );
+    expect(result.skipped.every((s) => s.reason === 'non-numeric')).toBe(true);
+  });
+
+  it('coerces numeric strings (e.g. "14") to integer strings', () => {
+    writePersisted({ healthRetentionDays: '14' });
+    const loader = require('../src/config/disk-settings-loader');
+    loader({ dataDir: TMP_DATA_DIR });
+    expect(process.env.HEALTH_HISTORY_RETENTION).toBe('14');
+    // Must be an integer-formatted string (not "14.7", "14x", etc.)
+    expect(Number.isInteger(parseInt(process.env.HEALTH_HISTORY_RETENTION, 10))).toBe(true);
+  });
+
+  it('is idempotent across multiple calls (once-guard)', () => {
+    writePersisted({ healthRetentionDays: 7 });
+    const loader = require('../src/config/disk-settings-loader');
+    const first = loader({ dataDir: TMP_DATA_DIR });
+    const second = loader({ dataDir: TMP_DATA_DIR });
+    expect(first.applied).toHaveLength(1);
+    expect(second.applied).toEqual([]);
+    expect(second.alreadyRun).toBe(true);
+  });
+
+  it('skips unknown fields without crashing', () => {
+    writePersisted({
+      healthRetentionDays: 14,
+      unknownField: 'whatever',
+      anotherUnknown: { nested: true },
+    });
+    const loader = require('../src/config/disk-settings-loader');
+    expect(() => loader({ dataDir: TMP_DATA_DIR })).not.toThrow();
+    expect(process.env.HEALTH_HISTORY_RETENTION).toBe('14');
+  });
+
+  it('returns a summary object with source path', () => {
+    writePersisted({ healthRetentionDays: 14 });
+    const loader = require('../src/config/disk-settings-loader');
+    const result = loader({ dataDir: TMP_DATA_DIR });
+    expect(result.source).toBe(path.join(TMP_DATA_DIR, 'disk-settings.json'));
+    expect(result.alreadyRun).toBe(false);
+  });
+
+  it('writes a boot summary to stderr when no logger is provided', () => {
+    writePersisted({ healthRetentionDays: 14, healthMaxEntries: 999 });
+    const stderrSpy = jest.spyOn(process.stderr, 'write').mockImplementation(() => true);
+
+    const loader = require('../src/config/disk-settings-loader');
+    loader({ dataDir: TMP_DATA_DIR });  // no logger passed
+
+    expect(stderrSpy).toHaveBeenCalledWith(
+      expect.stringMatching(/^\[disk-settings-loader\] rehydrated 2 setting/),
+    );
+    stderrSpy.mockRestore();
+  });
+});

dashcaddy-api/routes/disk-settings.js

@@ -2,6 +2,12 @@ const express = require('express');
 const router = express.Router();
 const fs = require('fs');
 const path = require('path');
+const platformPaths = require('../platform-paths');
+
+// DC-048 — the canonical disk-settings.json path. Shared by GET + POST.
+function getSettingsFile() {
+  return path.join(platformPaths.dataDir, 'disk-settings.json');
+}
 
 // GET current disk settings + actual disk usage
 router.get('/', (req, res) => {
@@ -9,7 +15,10 @@ router.get('/', (req, res) => {
     const settings = {
       healthCheckInterval: parseInt(process.env.HEALTH_CHECK_INTERVAL || '30000'),
       healthMaxEntries: parseInt(process.env.HEALTH_MAX_ENTRIES || '500'),
-      healthRetentionDays: parseInt(process.env.HEALTH_HISTORY_RETENTION || '14'),
+      // DC-048 — align route default to engine default (health-checker.js:34
+      // reads 30 from env when unset; the route previously showed 14 as the
+      // "no override" value, which silently disagreed with the engine).
+      healthRetentionDays: parseInt(process.env.HEALTH_HISTORY_RETENTION || '30'),
       statsMaxEntries: parseInt(process.env.CONTAINER_STATS_MAX_ENTRIES || '500'),
       auditMaxEntries: parseInt(process.env.AUDIT_MAX_ENTRIES || '1000'),
       backupMaxStorageBytes: parseInt(process.env.BACKUP_MAX_STORAGE_BYTES || '0'),
@@ -31,7 +40,7 @@ router.get('/', (req, res) => {
     } catch {}
 
     // Load persisted settings
-    const settingsFile = path.join(path.dirname(require('../config/paths').configFile), 'disk-settings.json');
+    const settingsFile = getSettingsFile();
     let persisted = {};
     try { persisted = JSON.parse(fs.readFileSync(settingsFile, 'utf8')); } catch {}
     
@@ -45,24 +54,37 @@ router.get('/', (req, res) => {
 router.post('/', (req, res) => {
   try {
     const { healthInterval, healthMaxEntries, healthRetentionDays, statsMaxEntries, auditMaxEntries } = req.body;
-    const updates = {};
 
-    if (healthInterval !== undefined) { updates.healthCheckInterval = parseInt(healthInterval); process.env.HEALTH_CHECK_INTERVAL = String(healthInterval); }
-    if (healthMaxEntries !== undefined) { updates.healthMaxEntries = parseInt(healthMaxEntries); process.env.HEALTH_MAX_ENTRIES = String(healthMaxEntries); }
-    if (healthRetentionDays !== undefined) { updates.healthRetentionDays = parseInt(healthRetentionDays); process.env.HEALTH_HISTORY_RETENTION = String(healthRetentionDays); }
-    if (statsMaxEntries !== undefined) { updates.statsMaxEntries = parseInt(statsMaxEntries); process.env.CONTAINER_STATS_MAX_ENTRIES = String(statsMaxEntries); }
-    if (auditMaxEntries !== undefined) { updates.auditMaxEntries = parseInt(auditMaxEntries); process.env.AUDIT_MAX_ENTRIES = String(auditMaxEntries); }
+    // DC-048 — coerce + validate EVERY numeric input before persisting.
+    // Without this gate, parseInt('abc') === NaN → String(NaN) === 'NaN' →
+    // process.env.HEALTH_CHECK_INTERVAL becomes 'NaN' at runtime AND the
+    // persisted file gets JSON.stringify({x: NaN}) === {"x": null} which
+    // the loader silently drops on next boot. Validation now rejects the
+    // request with 400 BEFORE any env mutation or file write.
+    const intField = (name, value) => {
+      const n = Number(value);
+      if (!Number.isFinite(n) || !Number.isInteger(n)) {
+        throw new Error(`${name} must be an integer (received ${JSON.stringify(value)})`);
+      }
+      return n;
+    };
+
+    const updates = {};
+    if (healthInterval !== undefined)      { const n = intField('healthInterval', healthInterval);      updates.healthCheckInterval = n; process.env.HEALTH_CHECK_INTERVAL = String(n); }
+    if (healthMaxEntries !== undefined)    { const n = intField('healthMaxEntries', healthMaxEntries);    updates.healthMaxEntries = n;    process.env.HEALTH_MAX_ENTRIES = String(n); }
+    if (healthRetentionDays !== undefined) { const n = intField('healthRetentionDays', healthRetentionDays); updates.healthRetentionDays = n; process.env.HEALTH_HISTORY_RETENTION = String(n); }
+    if (statsMaxEntries !== undefined)     { const n = intField('statsMaxEntries', statsMaxEntries);     updates.statsMaxEntries = n;     process.env.CONTAINER_STATS_MAX_ENTRIES = String(n); }
+    if (auditMaxEntries !== undefined)     { const n = intField('auditMaxEntries', auditMaxEntries);     updates.auditMaxEntries = n;     process.env.AUDIT_MAX_ENTRIES = String(n); }
 
     // Persist to file
-    const paths = require('../config/paths');
-    const settingsFile = path.join(path.dirname(paths.configFile), 'disk-settings.json');
+    const settingsFile = getSettingsFile();
     let existing = {};
     try { existing = JSON.parse(fs.readFileSync(settingsFile, 'utf8')); } catch {}
     fs.writeFileSync(settingsFile, JSON.stringify({ ...existing, ...updates }, null, 2));
 
     res.json({ success: true, updated: updates, message: 'Settings saved. Some changes apply on next container restart.' });
   } catch (e) {
-    res.status(500).json({ success: false, error: e.message });
+    res.status(e.statusCode || 400).json({ success: false, error: e.message });
   }
 });
 

dashcaddy-api/src/app.js

@@ -19,6 +19,11 @@ const { asyncHandler } = require('./utils/async-handler');
 // Managers and utilities
 const StateManager = require('./managers/state-manager');
 const platformPaths = require('../platform-paths');
+// DC-048 — rehydrate process.env from disk-settings.json BEFORE any engine
+// module reads env at module-load time. Must run before health-checker,
+// audit-logger, and the backups route module (backups.js reads
+// BACKUP_MAX_STORAGE_BYTES at module load too).
+require('./config/disk-settings-loader')();
 const { LicenseManager } = require('./managers/license-manager');
 const credentialManager = require('./managers/credential-manager');
 const authManager = require('./managers/auth-manager');

dashcaddy-api/src/config/disk-settings-loader.js

@@ -0,0 +1,193 @@
+/**
+ * Disk Settings Bootstrap Loader (DC-048)
+ *
+ * Reads /app/data/disk-settings.json (resolved via platform-paths.dataDir)
+ * at boot time and rehydrates process.env values for engine settings that
+ * were previously captured only via in-memory process.env writes on the
+ * POST /api/v1/disk-settings route.
+ *
+ * Why this exists:
+ *   health-checker.js, audit-logger.js, and backups.js all read
+ *   `process.env.HEALTH_*` / `process.env.AUDIT_MAX_ENTRIES` /
+ *   `process.env.BACKUP_MAX_STORAGE_BYTES` at MODULE LOAD. The previous
+ *   POST handler only wrote those values to process.env at runtime, so
+ *   any value persisted to disk-settings.json was silently discarded on
+ *   every container restart. Users who saved "Health Retention = 7 days"
+ *   would see 30 days come back at the next boot.
+ *
+ * Behavior:
+ *   - Only sets a key if process.env[key] is already UNDEFINED. Explicit
+ *     container / compose env still wins on cold boot (so operators can
+ *     override via the env without editing disk-settings.json).
+ *   - Logs a single INFO line at boot summarizing what was rehydrated.
+ *   - Never throws. A missing or malformed disk-settings.json is logged
+ *     and ignored — the engine falls back to its compiled-in defaults.
+ *
+ * Order of operations in src/app.js:
+ *   require('./config/disk-settings-loader')();   // ← MUST be before any
+ *   const healthChecker = require('./monitoring/health-checker');         //  engine module
+ *   const auditLogger   = require('./security/audit-logger');            //  that reads env
+ *
+ * Mapping table (mirrors the POST handler in routes/disk-settings.js):
+ *   disk-settings.json field  →  process.env key
+ *   healthCheckInterval       →  HEALTH_CHECK_INTERVAL      (ms)
+ *   healthMaxEntries          →  HEALTH_MAX_ENTRIES         (entries)
+ *   healthRetentionDays       →  HEALTH_HISTORY_RETENTION   (days)
+ *   statsMaxEntries           →  CONTAINER_STATS_MAX_ENTRIES(entries; reserved, no engine consumer yet)
+ *   auditMaxEntries           →  AUDIT_MAX_ENTRIES          (entries)
+ *   backupMaxStorageBytes     →  BACKUP_MAX_STORAGE_BYTES   (bytes)
+ *
+ * Returns an object describing what was applied — useful for tests + boot logs.
+ */
+
+'use strict';
+
+const fs = require('fs');
+const path = require('path');
+
+const ENV_MAP = Object.freeze({
+  healthCheckInterval:   'HEALTH_CHECK_INTERVAL',
+  healthMaxEntries:      'HEALTH_MAX_ENTRIES',
+  healthRetentionDays:   'HEALTH_HISTORY_RETENTION',
+  statsMaxEntries:       'CONTAINER_STATS_MAX_ENTRIES',
+  auditMaxEntries:       'AUDIT_MAX_ENTRIES',
+  backupMaxStorageBytes: 'BACKUP_MAX_STORAGE_BYTES',
+});
+
+// Numeric fields MUST be coerced to integers; a stray string in disk-settings.json
+// would otherwise land in process.env as a string and the next
+// parseInt(process.env.X || 'N') in the engine would silently fall back to N
+// when the value is unparseable. Defensive coercion here keeps the engine
+// consistent with the values the user just saved.
+const NUMERIC_FIELDS = Object.freeze([
+  'healthCheckInterval',
+  'healthMaxEntries',
+  'healthRetentionDays',
+  'statsMaxEntries',
+  'auditMaxEntries',
+  'backupMaxStorageBytes',
+]);
+
+function loadPersistedSettings(dataDir) {
+  if (!dataDir) return null;
+  const settingsFile = path.join(dataDir, 'disk-settings.json');
+  if (!fs.existsSync(settingsFile)) return null;
+  try {
+    const raw = fs.readFileSync(settingsFile, 'utf8');
+    const parsed = JSON.parse(raw);
+    if (parsed && typeof parsed === 'object' && !Array.isArray(parsed)) {
+      return parsed;
+    }
+    return null;
+  } catch (err) {
+    // Log + swallow. The engine's compiled-in defaults are the safe fallback.
+    // Do NOT re-throw — a malformed settings file must not stop the API from booting.
+    process.stderr.write(
+      `[disk-settings-loader] WARN: failed to parse ${settingsFile}: ${err.message}; using engine defaults\n`,
+    );
+    return null;
+  }
+}
+
+/**
+ * Resolve dataDir WITHOUT importing platform-paths at the top level — the loader
+ * is required very early in app.js, before platform-paths has been fully loaded
+ * by sibling modules. A local require is safe (it's idempotent and side-effect
+ * free — platform-paths is pure constants).
+ */
+function resolveDataDir() {
+  try {
+    // eslint-disable-next-line global-require
+    const platformPaths = require('../../platform-paths');
+    return platformPaths.dataDir;
+  } catch {
+    return process.env.DATA_DIR || '/etc/dashcaddy';
+  }
+}
+
+function applyToEnv(persisted, { logger } = {}) {
+  const applied = [];
+  const skipped = [];
+  if (!persisted) return { applied, skipped };
+
+  for (const [field, envKey] of Object.entries(ENV_MAP)) {
+    if (!Object.prototype.hasOwnProperty.call(persisted, field)) continue;
+    let value = persisted[field];
+    if (value === null || value === undefined || value === '') continue;
+
+    if (NUMERIC_FIELDS.includes(field)) {
+      const n = Number(value);
+      if (!Number.isFinite(n)) {
+        skipped.push({ field, envKey, reason: 'non-numeric' });
+        continue;
+      }
+      value = String(Math.trunc(n));
+    } else {
+      value = String(value);
+    }
+
+    if (process.env[envKey] !== undefined && process.env[envKey] !== '') {
+      // Explicit env wins over persisted file. This is the only way operators
+      // can override a saved value without first deleting the file.
+      skipped.push({ field, envKey, reason: 'env-already-set' });
+      continue;
+    }
+
+    process.env[envKey] = value;
+    applied.push({ field, envKey, value });
+  }
+
+  return { applied, skipped };
+}
+
+let hasRun = false;
+
+/**
+ * Run the loader once. Idempotent — second invocation is a no-op so test
+ * suites that `jest.resetModules()` between cases don't re-apply values
+ * from a stale persisted file across tests.
+ */
+function applyDiskSettings(options = {}) {
+  if (hasRun) return { applied: [], skipped: [], alreadyRun: true };
+  hasRun = true;
+
+  const dataDir = options.dataDir || resolveDataDir();
+  const persisted = loadPersistedSettings(dataDir);
+  const { applied, skipped } = applyToEnv(persisted, options);
+
+  const summary = {
+    applied,
+    skipped,
+    source: persisted ? path.join(dataDir, 'disk-settings.json') : null,
+    alreadyRun: false,
+  };
+
+  if (applied.length > 0) {
+    const msg = `[disk-settings-loader] rehydrated ${applied.length} setting(s) from ${summary.source}: `
+      + applied.map((a) => `${a.field}=${a.value}`).join(', ');
+    // Always emit to stderr at boot — operators need to see rehydration
+    // regardless of whether the app logger is wired yet (the loader runs
+    // at module-load time, before app.js createApp() builds the logger).
+    if (options.logger) options.logger.info(msg);
+    else process.stderr.write(msg + '\n');
+  } else if (skipped.length === 0 && !persisted) {
+    // No persisted file: silent. (No boot noise when nothing to do.)
+  } else if (skipped.length > 0) {
+    const msg = `[disk-settings-loader] skipped ${skipped.length} setting(s) (env-already-set or non-numeric): `
+      + skipped.map((s) => `${s.envKey}(${s.reason})`).join(', ');
+    if (options.logger) options.logger.info(msg);
+    else process.stderr.write(msg + '\n');
+  }
+
+  return summary;
+}
+
+// Exposed for tests that need to reset the once-guard between cases.
+function _resetForTesting() {
+  hasRun = false;
+}
+
+module.exports = applyDiskSettings;
+module.exports.applyDiskSettings = applyDiskSettings;
+module.exports._resetForTesting = _resetForTesting;
+module.exports.ENV_MAP = ENV_MAP;

status/js/disk-settings.js

@@ -59,7 +59,7 @@
         <div style="display:grid;gap:16px;">
           ${settingRow('Health Check Interval', 'healthInterval', c.healthCheckInterval, 'seconds', Math.round((c.healthCheckInterval||30000)/1000), 5, 300)}
           ${settingRow('Max Health Entries/Service', 'healthMaxEntries', c.healthMaxEntries, 'entries', c.healthMaxEntries||500, 50, 5000)}
-          ${settingRow('Health Retention', 'healthRetentionDays', c.healthRetentionDays, 'days', c.healthRetentionDays||14, 1, 90)}
+          ${settingRow('Health Retention', 'healthRetentionDays', c.healthRetentionDays, 'days', c.healthRetentionDays||30, 1, 90)}
           ${settingRow('Max Stats Entries', 'statsMaxEntries', c.statsMaxEntries, 'entries', c.statsMaxEntries||500, 100, 10000)}
           ${settingRow('Max Audit Entries', 'auditMaxEntries', c.auditMaxEntries, 'entries', c.auditMaxEntries||1000, 100, 10000)}
         </div>