fix(ook): address upstream PR review — SDR tracking, validation, cleanup, XSS

Critical:
- Pass sdr_type_str to claim/release_sdr_device (was missing 3rd arg)
- Add ook_active_sdr_type module-level var for proper device registry tracking
- Add server-side range validation on all timing params via validate_positive_int

Major:
- Extract cleanup_ook() function for full teardown (stop_event, pipes, process,
  SDR release) — called from both stop_ook() and kill_all()
- Replace Popen monkey-patching with module-level _ook_stop_event/_ook_parser_thread
- Fix XSS: define local _esc() fallback in ook.js, never use raw innerHTML
- Remove dead inversion code path in utils/ook.py (bytes.fromhex on same
  string that already failed decode — could never produce a result)

Minor:
- Status event key 'status' → 'text' for consistency with other modules
- Parser thread logging: debug → warning for missing code field and errors
- Parser thread emits status:stopped on exit (normal EOF or crash)
- Add cache-busting ?v={{ version }}&r=ook1 to ook.js script include
- Fix gain/ppm comparison: != '0' (string) → != 0 (number)

Tests: 22 → 33 (added start success, stop with process, SSE stream,
timing range validation, stopped-on-exit event)

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

app.py

@@ -896,12 +896,16 @@ def kill_all() -> Response:
     with morse_lock:
         morse_process = None
 
-    # Reset OOK state
+    # Reset OOK state (full cleanup: parser thread, pipes, SDR release)
     with ook_lock:
-        if ook_process:
-            safe_terminate(ook_process)
-            unregister_process(ook_process)
-        ook_process = None
+        try:
+            from routes.ook import cleanup_ook
+            cleanup_ook(emit_status=False)
+        except Exception:
+            if ook_process:
+                safe_terminate(ook_process)
+                unregister_process(ook_process)
+            ook_process = None
 
     # Reset APRS state
     with aprs_lock: