Web UI v4.1.6: Admin settings, nav icons, air-gap ready

Admin System Settings page:
- New /admin/settings route with channel key config
- QR code export with tiled print sheet (4x5 on US Letter)
- Server config display (HTTPS, port, auth, DCT/QR status)
- Environment info (version, Python, platform, KDF)

Navigation improvements:
- Icon-only nav with floating labels on hover
- Gold labels slide down below icons
- Gradient pill background on hover

Air-gap ready:
- All vendor libs now local (Bootstrap CSS/JS, Icons, html5-qrcode)
- QRious library for QR generation
- No external CDN dependencies

Other changes:
- Moved About link from nav to footer
- Channel QR export moved from about.html to admin/settings.html
- Print sheet button for QR codes (tiled US Letter output)
- Dev runner script (dev_run.sh) with r/q hotkeys
- Fixed navbar dropdown z-index

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontends/web/dev_run.sh

@@ -0,0 +1,52 @@
+#!/bin/bash
+# Stegasoo Web Frontend - Development Runner
+# Press 'r' to restart, 'q' to quit (single keypress, no Enter needed)
+
+cd "$(dirname "$0")"
+
+PID=""
+
+cleanup() {
+    echo -e "\n\033[33mShutting down...\033[0m"
+    [[ -n "$PID" ]] && kill "$PID" 2>/dev/null
+    stty sane 2>/dev/null
+    exit 0
+}
+
+trap cleanup SIGINT SIGTERM EXIT
+
+start_server() {
+    clear
+    echo -e "\033[36m┌──────────────────────────────────────┐\033[0m"
+    echo -e "\033[36m│  Stegasoo Dev Server                 │\033[0m"
+    echo -e "\033[36m│  \033[0m[r] restart  [q] quit\033[36m              │\033[0m"
+    echo -e "\033[36m└──────────────────────────────────────┘\033[0m"
+
+    pkill -f "python app.py" 2>/dev/null
+    sleep 0.3
+
+    python app.py 2>&1 &
+    PID=$!
+    echo -e "\033[32m✓ Running on http://localhost:5000 (PID: $PID)\033[0m\n"
+}
+
+start_server
+
+# Single keypress mode
+stty -echo -icanon time 0 min 0
+
+while true; do
+    key=$(dd bs=1 count=1 2>/dev/null)
+    case "$key" in
+        r|R) start_server ;;
+        q|Q) cleanup ;;
+    esac
+
+    # Check if crashed
+    if [[ -n "$PID" ]] && ! kill -0 "$PID" 2>/dev/null; then
+        echo -e "\033[31m✗ Crashed! Press 'r' to restart\033[0m"
+        PID=""
+    fi
+
+    sleep 0.1
+done