[grade=A] P2-5: fix 4 test handle leaks in log-digest.js + sweep remaining console calls

Root cause: setTimeout in start() (line 74) created an initial-collection
timer that was never stored in an instance property, so stop() could not
clear it. Tests called start() → afterEach stop(), but the orphaned handle
kept the test process alive (4 leaked handles across 4 test cases).

Fix: store as this._initialTimeout, clear in stop() alongside digestTimeout.

Also replaced 3 remaining console.error calls in log-digest.js with
structured log.error tagged 'logdigest' (was missed in P1-8 sweep).

1539/1539 tests pass. 0 open handles (--detectOpenHandles clean).

dashcaddy-api/src/security/log-digest.js

@@ -11,6 +11,7 @@ const fs = require('fs');
 const fsp = require('fs').promises;
 const path = require('path');
 const { DOCKER } = require('../utilities/constants');
+const { log } = require('../utils/logging');
 
 const docker = new Docker();
 
@@ -63,7 +64,7 @@ class LogDigest extends EventEmitter {
     // Collect logs every hour
     this.collectInterval = setInterval(() => {
       this._collectHourlyLogs().catch(e =>
-        console.error('[LogDigest] Hourly collection failed:', e.message)
+        log.error('logdigest', e, { phase: 'hourlyCollect' })
       );
     }, DOCKER.DIGEST.COLLECT_INTERVAL);
 
@@ -71,7 +72,7 @@ class LogDigest extends EventEmitter {
     this._scheduleDailyDigest();
 
     // Run initial collection after 2 minutes
-    setTimeout(() => {
+    this._initialTimeout = setTimeout(() => {
       if (this.running) {
         this._collectHourlyLogs().catch(() => {});
       }
@@ -89,6 +90,10 @@ class LogDigest extends EventEmitter {
       clearTimeout(this.digestTimeout);
       this.digestTimeout = null;
     }
+    if (this._initialTimeout) {
+      clearTimeout(this._initialTimeout);
+      this._initialTimeout = null;
+    }
   }
 
   /**
@@ -195,7 +200,7 @@ class LogDigest extends EventEmitter {
         hourSummary.services[appId] = serviceSummary;
       }
     } catch (e) {
-      console.error('[LogDigest] Container enumeration failed:', e.message);
+      log.error('logdigest', e, { phase: 'enumerateContainers' });
     }
 
     // Add to ring buffer
@@ -258,7 +263,7 @@ class LogDigest extends EventEmitter {
     const delay = next.getTime() - now.getTime();
     this.digestTimeout = setTimeout(() => {
       this.generateDailyDigest().catch(e =>
-        console.error('[LogDigest] Daily digest generation failed:', e.message)
+        log.error('logdigest', e, { phase: 'dailyDigest' })
       );
       // Reschedule for tomorrow
       if (this.running) this._scheduleDailyDigest();