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>

memory/kb/index.json

@@ -1,5 +1,18 @@
 {
   "notes": [
+    {
+      "file": "notes-data/tools/infrastructure.md",
+      "title": "Infrastructură (Proxmox + Docker)",
+      "date": "2026-08-23",
+      "tags": [],
+      "domains": [],
+      "types": [],
+      "category": "tools",
+      "project": null,
+      "subdir": null,
+      "video": "",
+      "tldr": "- Orice operație distructivă"
+    },
     {
       "file": "notes-data/projects/lfm2.5-230m-summarization-eval.md",
       "title": "LFM2.5-230M — evaluare ca preprocesor de rezumat / fallback conversațional (2026-08-21)",
@@ -1444,19 +1457,6 @@
       "video": "",
       "tldr": "*Instrumentale clasice și cinematic — Einaudi, Vangelis, Hisaishi, Tiersen, Secret Garden.*"
     },
-    {
-      "file": "notes-data/tools/infrastructure.md",
-      "title": "Infrastructură (Proxmox + Docker)",
-      "date": "2026-04-26",
-      "tags": [],
-      "domains": [],
-      "types": [],
-      "category": "tools",
-      "project": null,
-      "subdir": null,
-      "video": "",
-      "tldr": "- Orice operație distructivă"
-    },
     {
       "file": "notes-data/coaching/2026-04-25-negativity-bias-reframing.md",
       "title": "Negativity Bias & Positive Reframing",