feat: add Generic OOK Signal Decoder module

New 'OOK Decoder' mode for capturing and decoding arbitrary OOK/ASK
signals using rtl_433's flex decoder with fully configurable pulse
timing. Covers PWM, PPM, and Manchester encoding schemes.

Backend (utils/ook.py, routes/ook.py):
- Configurable modulation: OOK_PWM, OOK_PPM, OOK_MC_ZEROBIT
- Full rtl_433 flex spec builder with user-supplied pulse timings
- Bit-inversion fallback for transmitters with swapped short/long mapping
- Optional frame deduplication for repeated transmissions
- SSE streaming via /ook/stream

Frontend (static/js/modes/ook.js, templates/partials/modes/ook.html):
- Live MSB/LSB bit-order toggle — re-renders all stored frames instantly
  without restarting the decoder
- Full-detail frame display: timestamp, bit count, hex, dotted ASCII
- Modulation selector buttons with encoding hint text
- Full timing grid: short, long, gap/reset, tolerance, min bits
- CSV export of captured frames
- Global SDR device panel injection (device, SDR type, rtl_tcp, bias-T)

Integration (app.py, routes/__init__.py, templates/):
- Globals: ook_process, ook_queue, ook_lock
- Registered blueprint, nav entries (desktop + mobile), welcome card
- ookOutputPanel in visuals area with bit-order toolbar

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app.py

@@ -213,6 +213,11 @@ meteor_process = None
 meteor_queue = queue.Queue(maxsize=QUEUE_MAX_SIZE)
 meteor_lock = threading.Lock()
 
+# Generic OOK signal decoder
+ook_process = None
+ook_queue = queue.Queue(maxsize=QUEUE_MAX_SIZE)
+ook_lock = threading.Lock()
+
 # Deauth Attack Detection
 deauth_detector = None
 deauth_detector_queue = queue.Queue(maxsize=QUEUE_MAX_SIZE)