audio-bridge: fix bluetoothd path + add session dbus + cleanup stale pid

- bluetoothd at /usr/lib/bluetooth/bluetoothd (not in PATH on alpine)
- Add session dbus via dbus-daemon --session (pipewire needs it)
- Clean up stale dbus.pid files on startup (host volume persists)

infra/audio-bridge/entrypoint.sh

@@ -1,36 +1,39 @@
 #!/bin/sh
 # audio-bridge entrypoint
-# Starts DBus, BlueZ, WirePlumber, then PipeWire. PA clients (librespot, mopidy)
-# connect via pipewire-pulse bridge on TCP localhost:4713.
+# Starts DBus (system + session), BlueZ, WirePlumber, then PipeWire.
+# PA clients (librespot, mopidy) connect via pipewire-pulse bridge on TCP localhost:4713.
 
 set -e
 
 mkdir -p /run/dbus /run/user/0
 chmod 0755 /run/dbus
 chmod 0700 /run/user/0
+# Clean up stale pid files from previous container runs (host volume persists).
+rm -f /run/dbus/dbus.pid /run/user/0/dbus.pid
 
-# System DBus (needed by bluetoothd, wireplumber, pipewire)
+# System DBus (needed by bluetoothd, wireplumber)
 dbus-daemon --system --fork
 sleep 0.5
 
+# Session DBus (needed by PipeWire for portal/jackdbus-detect modules).
+# Use XDG_RUNTIME_DIR=/run/user/0 so dbus-launch puts socket there.
+export XDG_RUNTIME_DIR=/run/user/0
+dbus-daemon --session --address=unix:path=/run/user/0/bus --fork --print-pid 3
+sleep 0.3
+
 # BlueZ (Bluetooth stack). --compat = legacy mode for older audio devices.
-# Disabled if no /dev/bluetooth/rfkill — wireplumber will skip BT modules.
+# Disabled if no /sys/class/bluetooth — wireplumber will skip BT modules.
 if [ -d /sys/class/bluetooth ]; then
-    bluetoothd --compat --nodetach &
+    /usr/lib/bluetooth/bluetoothd --compat --nodetach &
     sleep 0.5
     echo "[audio-bridge] bluetoothd started"
 else
     echo "[audio-bridge] no bluetooth hardware — skipping bluetoothd"
 fi
 
-# PipeWire runtime env
-export XDG_RUNTIME_DIR=/run/user/0
-export DBUS_SYSTEM_BUS_ADDRESS=unix:path=/run/dbus/system_bus_socket
-
-# WirePlumber first (it manages PipeWire session/policy, loads BT modules)
+# WirePlumber first (manages PipeWire session/policy, loads BT modules on demand)
 wireplumber &
 sleep 1
 
-# PipeWire last. The pipewire-pulse package auto-loads the PA bridge module
-# so PA clients (librespot, mopidy) can connect via TCP localhost:4713.
+# PipeWire last. pipewire-pulse auto-loads PA bridge so clients connect via TCP 4713.
 exec pipewire