Cleanup repo + harden offline install and watchdog

Repo hygiene:
- Remove dead scripts (.wait-for-display, .display-keepalive, .keep-screen-alive)
- Remove stale backup/scratch (install.sh.bak, New.txt, stale .pyc)
- Stop tracking machine-specific/generated state (config/app_config.json,
  playlists/server_playlist.json, src/player_auth.json, generated launchers)
- Prune duplicate wheel versions (one per package)
- Reorganize working_files -> dev/, dev/tests/, documentation/dev-notes/, scripts/
- Extend .gitignore; fix no-op rules in repo/.gitignore

Offline install (install.sh):
- Non-fatal system-dep step; per-package apt retry; .deb bundle install
- Skip pip self-upgrade offline; guard online fallbacks behind connectivity probe
- Dependency-free fetch_url (curl/wget/urllib); --no-reboot flag
- Fix corrupted literal backslash-bang escapes (shebangs, test -f, banner)
- Idempotent cron install (no more stacked @reboot lines)

Autostart / watchdog:
- start.sh: single-instance flock lock (.player_watchdog.lock) acquired only
  after a display is confirmed, preventing parallel watchdogs
- Set XDG_RUNTIME_DIR when missing; exit early if headless
- run_player.sh: activate .venv; stop_player.sh: clear lock file

dev/analyze_playlist.py

@@ -0,0 +1,35 @@
+#!/usr/bin/env python3
+"""Analyze what's happening with the playlist download."""
+
+import json
+
+# Check the saved playlist
+playlist_file = 'playlists/server_playlist_v8.json'
+print("=" * 80)
+print("SAVED PLAYLIST ANALYSIS")
+print("=" * 80)
+
+with open(playlist_file, 'r') as f:
+    data = json.load(f)
+
+print(f"\nVersion: {data.get('version', 'N/A')}")
+print(f"Items in playlist: {len(data.get('playlist', []))}")
+
+print("\nPlaylist items:")
+for idx, item in enumerate(data.get('playlist', []), 1):
+    print(f"\n{idx}. File: {item.get('file_name', 'N/A')}")
+    print(f"   URL: {item.get('url', 'N/A')}")
+    print(f"   Duration: {item.get('duration', 'N/A')}s")
+
+print("\n" + "=" * 80)
+print("\n⚠️  ISSUE: Server has 5 files, but only 3 are saved!")
+print("\nPossible reasons:")
+print("1. Server sent only 3 files")
+print("2. 2 files failed to download and were skipped")
+print("3. Download function has a bug")
+print("\nThe download_media_files() function in get_playlists_v2.py:")
+print("- Downloads from the 'url' field in the playlist")
+print("- If download fails, it SKIPS the file (continues)")
+print("- Only successfully downloaded files are added to updated_playlist")
+print("\nThis means 2 files likely had invalid URLs or download errors!")
+print("=" * 80)