Refactor entire project for Docker-native operation

Complete Docker-first refactor of the 6,800-line management script:

Core Architecture:
- Added is_docker() detection (/.dockerenv + /proc/1/cgroup check)
- Added asterisk_running() helper replacing all systemctl is-active calls
- Moved restart_asterisk_safe() to top-level with Docker/bare-metal branches
- Added webadmin_running(), start_webadmin(), stop_webadmin(), restart_webadmin()
  for process-based web admin management (replaces systemd service)

Functions Refactored (Docker-aware):
- fix_asterisk_systemd(): no-op in Docker (no systemd)
- install_asterisk_packages(): skips apt in Docker (pre-installed)
- install_baresip_packages(): skips in Docker (no local audio client)
- open_firewall_ports(): skips ufw in Docker (host responsibility)
- configure_asterisk(): skips systemctl enable in Docker
- enable_client_services(): skips entirely in Docker (no kiosk client)
- configure_baresip(): skips entirely in Docker
- configure_local_client(): shows error with guidance to use mobile clients
- run_client_diagnostics(): redirects to vpn-diagnostics
- fix_audio_manually(): not available in Docker (no audio hardware)
- uninstall_menu(): shows Docker-specific reset options
- manual_update_asterisk(): shows Docker rebuild instructions
- create_web_admin_service(): no-op in Docker (process-managed)
- web_admin_menu(): uses start/stop/restart_webadmin() instead of systemctl

Menu System:
- show_main_menu(): Docker-specific status display (Asterisk, Web Admin,
  VPN ICE status) with streamlined menu (no Client Settings option)
- submenu_install(): Docker shows Configure/Reset instead of Install/Uninstall
- submenu_tools(): Docker shows Room Directory, Update, VPN Diagnostics,
  DNS Whitelist (hides audio tools that need hardware)

Entrypoint:
- Proper signal trapping (SIGTERM/SIGINT) for clean shutdown
- Generates all Asterisk configs with STUN/ICE support from env vars
- Creates default device categories on first run
- Starts web admin as background process with env-based config

Dockerfile:
- Added lsof dependency (needed for port management)
- Added STUN port 3478 exposure
- Ensured /.dockerenv marker exists

Backward compatible: bare-metal installs work exactly as before.

https://claude.ai/code/session_01Vm6NLaQuzM4VosAotqS1q8

Dockerfile

@@ -6,6 +6,8 @@
 #   docker compose up -d                    # Asterisk only
 #   docker compose --profile stun up -d     # Asterisk + self-hosted STUN
 #   docker exec -it easy-asterisk easy-asterisk  # Interactive management
+#   docker exec -it easy-asterisk vpn-diagnostics # VPN diagnostics
+#   docker exec -it easy-asterisk dns-whitelist   # DNS whitelist check
 # ================================================================
 
 FROM ubuntu:24.04
@@ -13,7 +15,7 @@ FROM ubuntu:24.04
 ENV DEBIAN_FRONTEND=noninteractive
 ENV LANG=C.UTF-8
 
-# Install Asterisk and dependencies (matches install_asterisk_packages)
+# Install Asterisk and all dependencies (matches install_asterisk_packages)
 RUN echo "exit 101" > /usr/sbin/policy-rc.d && chmod +x /usr/sbin/policy-rc.d && \
     apt-get update && \
     apt-get install -y --no-install-recommends \
@@ -30,6 +32,7 @@ RUN echo "exit 101" > /usr/sbin/policy-rc.d && chmod +x /usr/sbin/policy-rc.d &&
         dnsutils \
         iputils-ping \
         procps \
+        lsof \
     && rm -rf /var/lib/apt/lists/* \
     && rm -f /usr/sbin/policy-rc.d \
     && ldconfig \
@@ -50,6 +53,9 @@ RUN mkdir -p \
         /var/spool/asterisk \
         /var/run/asterisk
 
+# Docker detection marker (used by is_docker() in the script)
+RUN touch /.dockerenv
+
 # Copy the main management script
 COPY easy-asterisk-v0.10.0.sh /usr/local/bin/easy-asterisk
 RUN chmod +x /usr/local/bin/easy-asterisk
@@ -73,6 +79,9 @@ EXPOSE 8080/tcp
 EXPOSE 8088/tcp
 EXPOSE 8089/tcp
 
+# STUN (if running coturn in same container)
+EXPOSE 3478/udp
+
 # RTP media range (use --network host in production for full range)
 # Docker port-mapping 10000 ports is impractical; host networking recommended
 EXPOSE 10000-10100/udp