fix(ook): address code review findings from Copilot PR review

- Fix XSS: escape ASCII output in innerHTML via escapeHtml()
- Fix deadlock: use put_nowait() for queue ops under ook_lock
- Fix SSE leak: add ook to moduleDestroyMap so switching modes
  closes the EventSource
- Fix RSSI: explicit null check preserves valid zero values in
  JSON export
- Add frame cap: trim oldest frames at 5000 to prevent unbounded
  memory growth on busy bands
- Validate timing params: wrap int() casts in try/except, return
  400 instead of 500 on invalid input
- Fix PWM hint: correct to short=0/long=1 matching rtl_433
  OOK_PWM convention (UI, JS hints, and cheat sheet)
- Fix inversion docstring: clarify fallback only applies when
  primary hex parse fails, not for valid decoded frames

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

templates/partials/modes/ook.html

@@ -57,7 +57,7 @@
             </div>
             <input type="hidden" id="ookEncoding" value="pwm">
             <p id="ookEncodingHint" class="info-text" style="font-size: 10px; color: var(--text-dim); margin-top: 4px;">
-                Short pulse = 1, long pulse = 0. Most common for ISM OOK.
+                Short pulse = 0, long pulse = 1. Most common for ISM OOK.
             </p>
         </div>
     </div>