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/tests/test_direct_api.py

@@ -0,0 +1,55 @@
+#!/usr/bin/env python3
+"""Direct API test to check server playlist."""
+
+import requests
+import json
+
+# Try with the saved auth
+auth_file = 'src/player_auth.json'
+with open(auth_file, 'r') as f:
+    auth_data = json.load(f)
+
+server_url = auth_data['server_url']
+auth_code = auth_data['auth_code']
+
+print("=" * 80)
+print("DIRECT API TEST")
+print("=" * 80)
+print(f"Server: {server_url}")
+print(f"Auth code: {auth_code[:20]}...")
+print()
+
+# Try to get playlist
+try:
+    url = f"{server_url}/api/player/playlist"
+    headers = {
+        'Authorization': f'Bearer {auth_code}'
+    }
+    
+    print(f"Fetching: {url}")
+    response = requests.get(url, headers=headers, timeout=10)
+    
+    print(f"Status: {response.status_code}")
+    
+    if response.status_code == 200:
+        data = response.json()
+        print(f"\nPlaylist version: {data.get('playlist_version', 'N/A')}")
+        print(f"Number of items: {len(data.get('playlist', []))}")
+        
+        print("\nPlaylist items:")
+        for idx, item in enumerate(data.get('playlist', []), 1):
+            print(f"\n  {idx}. {item.get('file_name', 'N/A')}")
+            print(f"     URL: {item.get('url', 'N/A')}")
+            print(f"     Duration: {item.get('duration', 'N/A')}s")
+        
+        # Save full response
+        with open('server_playlist_full.json', 'w') as f:
+            json.dump(data, f, indent=2)
+        print(f"\nFull response saved to: server_playlist_full.json")
+    else:
+        print(f"Error: {response.text}")
+        
+except Exception as e:
+    print(f"Error: {e}")
+
+print("\n" + "=" * 80)