feat(dashboard): endpoint de download fișiere binare + tool epub-to-audio

- dashboard/handlers/files.py: handle_files_download() servește mp3/wav/zip
  din WORKSPACE_DIR cu Content-Disposition attachment, resolve dedicat
  (nu _resolve_sandboxed, care nu ajunge niciodată la WORKSPACE_DIR)
- dashboard/api.py: rutează /api/files/download
- tools/epub_to_audio.py: tool nou de conversie EPUB → audio
- cron/jobs.json, memory/kb/index.json: stare auto-generată (job runs,
  regenerare index KB)

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

cron/jobs.json

@@ -11,9 +11,9 @@
     "report_on": "changes",
     "timeout": 120,
     "enabled": true,
-    "last_run": "2026-08-21T16:00:00.000757+00:00",
+    "last_run": "2026-08-27T16:00:00.002423+00:00",
     "last_status": "ok",
-    "next_run": "2026-08-22T10:00:00+00:00"
+    "next_run": "2026-08-28T10:00:00+00:00"
   },
   {
     "name": "security-audit-daily",
@@ -43,9 +43,9 @@
     "report_on": "never",
     "timeout": 120,
     "enabled": true,
-    "last_run": "2026-08-22T03:30:00.002627+00:00",
+    "last_run": "2026-08-27T03:30:00.002353+00:00",
     "last_status": "ok",
-    "next_run": "2026-08-23T03:30:00+00:00"
+    "next_run": "2026-08-28T03:30:00+00:00"
   },
   {
     "name": "archive-tasks-daily",
@@ -59,9 +59,9 @@
     "report_on": "changes",
     "timeout": 60,
     "enabled": true,
-    "last_run": "2026-08-22T03:00:00.001220+00:00",
+    "last_run": "2026-08-27T03:00:00.001621+00:00",
     "last_status": "ok",
-    "next_run": "2026-08-23T03:00:00+00:00"
+    "next_run": "2026-08-28T03:00:00+00:00"
   },
   {
     "name": "backup-config",
@@ -75,9 +75,9 @@
     "report_on": "never",
     "timeout": 120,
     "enabled": true,
-    "last_run": "2026-08-22T02:00:00.001599+00:00",
+    "last_run": "2026-08-27T02:00:00.000911+00:00",
     "last_status": "ok",
-    "next_run": "2026-08-23T02:00:00+00:00"
+    "next_run": "2026-08-28T02:00:00+00:00"
   },
   {
     "name": "insights-extract",
@@ -243,9 +243,9 @@
     "prompt": "Heartbeat check. Rulează src/heartbeat.py printr-un scurt raport de status.\nDacă nu e nimic de raportat (email=0, calendar nu are evenimente <2h, kb ok), răspunde doar cu HEARTBEAT_OK și oprește-te — nu trimite mesaj.\nDacă e ceva: raport scurt pe Discord #echo-work.",
     "allowed_tools": [],
     "enabled": true,
-    "last_run": "2026-08-22T06:00:00.001316+00:00",
+    "last_run": "2026-08-27T14:00:00.002158+00:00",
     "last_status": "ok",
-    "next_run": "2026-08-22T10:00:00+00:00"
+    "next_run": "2026-08-27T18:00:00+00:00"
   },
   {
     "name": "night-execute",