feat(debug): GUI toggle for DRED verbose logs + macOS mic permission

DRED verbose logs (off by default — keeps logcat clean in normal use):
- wzp-codec: DRED_VERBOSE_LOGS atomic flag with dred_verbose_logs() /
  set_dred_verbose_logs() helpers
- opus_enc: gate "DRED enabled" + libopus version logs behind the flag
- desktop/src-tauri/engine.rs: gate DredRecvState parse log,
  reconstruction log, classical PLC log, and DRED-counter fields in
  the Android recv heartbeat (non-verbose path still logs basic recv
  stats)
- Tauri commands set_dred_verbose_logs / get_dred_verbose_logs
- Settings panel gets a "DRED debug logs (verbose, dev only)"
  checkbox; preference persists in wzp-settings localStorage and is
  pushed to Rust on save and on app boot

macOS mic permission:
- Add desktop/src-tauri/Info.plist with NSMicrophoneUsageDescription.
  Without it, modern macOS silently denies CoreAudio capture for
  ad-hoc-signed Tauri builds — capture starts but every callback
  hands you zeros. Symptom: phones could not hear desktop client,
  desktop could still hear phones (playout has no TCC gate). The
  Tauri 2 bundler auto-merges this file into WarzonePhone.app's
  Contents/Info.plist on the next build, so first launch will pop
  the standard mic prompt.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

desktop/index.html

@@ -169,6 +169,10 @@
               <input id="s-agc" type="checkbox" checked />
               Automatic Gain Control
             </label>
+            <label class="checkbox">
+              <input id="s-dred-debug" type="checkbox" />
+              DRED debug logs (verbose, dev only)
+            </label>
           </div>
           <div class="settings-section">
             <h3>Identity</h3>