feat: WiFi Locate mode, mobile nav groups, v2.24.0

Add WiFi Locate mode for locating access points by BSSID with real-time
signal meter, distance estimation, RSSI history chart, and audio
proximity tones. Includes hand-off from WiFi detail drawer, environment
presets (Free Space/Outdoor/Indoor), and signal-lost detection.

Also includes:
- Mobile navigation reorganized into labeled groups (SIG/TRK/SPC/WIFI/INTEL/SYS)
- flask-limiter made optional with graceful degradation
- Fix radiosonde setup missing semver Python dependency
- Documentation updates (FEATURES, USAGE, UI_GUIDE, GitHub Pages site)

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

Dockerfile

@@ -204,7 +204,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     && cd /tmp \
     && git clone --depth 1 https://github.com/projecthorus/radiosonde_auto_rx.git \
     && cd radiosonde_auto_rx/auto_rx \
-    && pip install --no-cache-dir -r requirements.txt \
+    && pip install --no-cache-dir -r requirements.txt semver \
     && bash build.sh \
     && mkdir -p /opt/radiosonde_auto_rx/auto_rx \
     && cp -r . /opt/radiosonde_auto_rx/auto_rx/ \