refactor(config): Extract configuration into src/config/ module

- Create src/config/paths.js for all file paths and env vars
- Create src/config/site.js for site configuration loading
- Create src/config/index.js as unified config export
- Prepare for server.js modularization (Phase 2.1)

Part of deslopification roadmap: break 1997-line server.js into layers

dashcaddy-api/src/config/index.js

@@ -0,0 +1,38 @@
+/**
+ * Centralized configuration module
+ * Exports all configuration loading and path resolution
+ */
+const paths = require('./paths');
+const site = require('./site');
+const { APP, LIMITS, TIMEOUTS, RETRIES, CADDY } = require('../../constants');
+
+// Load logging level
+const LOG_LEVELS = { debug: 0, info: 1, warn: 2, error: 3 };
+const LOG_LEVEL = LOG_LEVELS[process.env.LOG_LEVEL || 'info'] || 1;
+
+const PORT = APP.PORT;
+const MAX_ERROR_LOG_SIZE = LIMITS.ERROR_LOG_SIZE;
+
+module.exports = {
+  // Paths
+  ...paths,
+  
+  // Site configuration
+  siteConfig: site.siteConfig,
+  loadSiteConfig: site.loadSiteConfig,
+  buildDomain: site.buildDomain,
+  buildServiceUrl: site.buildServiceUrl,
+  
+  // App constants
+  PORT,
+  LOG_LEVELS,
+  LOG_LEVEL,
+  MAX_ERROR_LOG_SIZE,
+  
+  // Re-export constants for convenience
+  APP,
+  LIMITS,
+  TIMEOUTS,
+  RETRIES,
+  CADDY,
+};

dashcaddy-api/src/config/paths.js

@@ -0,0 +1,42 @@
+/**
+ * Platform-specific paths and environment variable configuration
+ */
+const path = require('path');
+const platformPaths = require('../../platform-paths');
+
+const CADDYFILE_PATH = process.env.CADDYFILE_PATH || platformPaths.caddyfile;
+const CADDY_ADMIN_URL = process.env.CADDY_ADMIN_URL || platformPaths.caddyAdminUrl;
+const SERVICES_FILE = process.env.SERVICES_FILE || platformPaths.servicesFile;
+const SERVICES_DIR = path.dirname(SERVICES_FILE);
+const CONFIG_FILE = process.env.CONFIG_FILE || path.join(SERVICES_DIR, 'config.json');
+const DNS_CREDENTIALS_FILE = process.env.DNS_CREDENTIALS_FILE || path.join(SERVICES_DIR, 'dns-credentials.json');
+const TAILSCALE_CONFIG_FILE = process.env.TAILSCALE_CONFIG_FILE || path.join(SERVICES_DIR, 'tailscale-config.json');
+const NOTIFICATIONS_FILE = process.env.NOTIFICATIONS_FILE || path.join(SERVICES_DIR, 'notifications.json');
+const TOTP_CONFIG_FILE = process.env.TOTP_CONFIG_FILE || path.join(SERVICES_DIR, 'totp-config.json');
+const ERROR_LOG_FILE = process.env.ERROR_LOG_FILE || path.join(__dirname, '../../dashcaddy-errors.log');
+const LICENSE_SECRET_FILE = process.env.LICENSE_SECRET_FILE || path.join(__dirname, '../../.license-secret');
+
+const BROWSE_ROOTS = (process.env.MEDIA_BROWSE_ROOTS || '')
+  .split(',')
+  .filter(r => r.includes('='))
+  .map(r => {
+    const eqIndex = r.indexOf('=');
+    const containerPath = r.slice(0, eqIndex).trim();
+    const hostPath = r.slice(eqIndex + 1).trim();
+    return { containerPath, hostPath };
+  });
+
+module.exports = {
+  CADDYFILE_PATH,
+  CADDY_ADMIN_URL,
+  SERVICES_FILE,
+  SERVICES_DIR,
+  CONFIG_FILE,
+  DNS_CREDENTIALS_FILE,
+  TAILSCALE_CONFIG_FILE,
+  NOTIFICATIONS_FILE,
+  TOTP_CONFIG_FILE,
+  ERROR_LOG_FILE,
+  LICENSE_SECRET_FILE,
+  BROWSE_ROOTS,
+};

dashcaddy-api/src/config/site.js

@@ -0,0 +1,79 @@
+/**
+ * Site configuration loader
+ * Loads and manages site-wide settings from config.json
+ */
+const fs = require('fs');
+const { validateConfig } = require('../../config-schema');
+const { CADDY } = require('../../constants');
+
+let siteConfig = {
+  tld: '.home',
+  caName: '',
+  dnsServerIp: '',
+  dnsServerPort: CADDY.DEFAULT_DNS_PORT,
+  dashboardHost: '',
+  timezone: 'UTC',
+  dnsServers: {},
+  configurationType: 'homelab',
+  domain: '',
+  routingMode: 'subdomain'
+};
+
+function loadSiteConfig(CONFIG_FILE, log) {
+  try {
+    if (fs.existsSync(CONFIG_FILE)) {
+      const raw = JSON.parse(fs.readFileSync(CONFIG_FILE, 'utf8'));
+
+      // Validate config and log any issues
+      const { valid, errors: configErrors, warnings: configWarnings } = validateConfig(raw);
+      if (log && log.warn) {
+        if (!valid) {
+          log.warn('config', 'Config validation errors', { errors: configErrors });
+        }
+        for (const w of configWarnings) {
+          log.warn('config', w);
+        }
+      }
+
+      siteConfig.tld = raw.tld || '.home';
+      if (!siteConfig.tld.startsWith('.')) siteConfig.tld = '.' + siteConfig.tld;
+      siteConfig.caName = raw.caName || '';
+      siteConfig.dnsServerIp = (raw.dns && raw.dns.ip) || '';
+      siteConfig.dnsServerPort = (raw.dns && raw.dns.port) || CADDY.DEFAULT_DNS_PORT;
+      siteConfig.dashboardHost = raw.dashboardHost || `status${siteConfig.tld}`;
+      siteConfig.timezone = raw.timezone || 'UTC';
+      siteConfig.dnsServers = raw.dnsServers || {};
+      siteConfig.configurationType = raw.configurationType || 'homelab';
+      siteConfig.domain = raw.domain || '';
+      siteConfig.routingMode = raw.routingMode || 'subdomain';
+      siteConfig.pylon = raw.pylon || null;
+    }
+  } catch (e) {
+    if (log && log.error) {
+      log.error('config', 'Failed to load site config', { error: e.message });
+    }
+  }
+}
+
+/** Build a domain from subdomain + configured TLD or public domain */
+function buildDomain(subdomain) {
+  if (siteConfig.configurationType === 'public' && siteConfig.domain) {
+    return `${subdomain}.${siteConfig.domain}`;
+  }
+  return `${subdomain}${siteConfig.tld}`;
+}
+
+/** Build full service URL (protocol + host + path) */
+function buildServiceUrl(subdomain) {
+  if (siteConfig.routingMode === 'subdirectory' && siteConfig.domain) {
+    return `https://${siteConfig.domain}/${subdomain}`;
+  }
+  return `https://${buildDomain(subdomain)}`;
+}
+
+module.exports = {
+  siteConfig,
+  loadSiteConfig,
+  buildDomain,
+  buildServiceUrl,
+};