fix(kiosk): clear stale Chromium profile lock so rename doesn't kill the kiosk (#98)

Chromium's SingletonLock is a symlink encoding <hostname>-<pid>. After a
node rename changes the OS hostname, the lock left from the previous
boot reads as "another computer" holding the profile; Chromium refuses
to start, --noerrdialogs hides the only dialog, and the kiosk
black-screens forever.

Two layers:
- kiosk launcher removes Singleton{Lock,Cookie,Socket} before every
  Chromium start (any prior owner is dead at that point — pkill at
  session start / loop respawn). Ships via ISO splice AND the binary's
  include_str! self-heal, so existing nodes get it with the next OTA.
- the rename handler clears the lock immediately as a hostname
  side-effect, covering nodes still running a pre-fix launcher.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

core/archipelago/src/api/rpc/system/handlers.rs

@@ -402,6 +402,16 @@ async fn sync_hostname_side_effects(hostname: &str) {
         Err(e) => warn!("/etc/hosts hostname sync failed: {}", e),
     }
 
+    // The kiosk Chromium's profile lock is a symlink encoding <hostname>-<pid>;
+    // after a rename the stale lock reads as "another computer" holding the
+    // profile, Chromium refuses to start (--noerrdialogs hides the dialog), and
+    // the kiosk black-screens on the next boot (#98). Clear it here — Chromium
+    // recreates the files on launch, and the kiosk launcher pkills any running
+    // instance before starting a new one.
+    for f in ["SingletonLock", "SingletonCookie", "SingletonSocket"] {
+        let _ = tokio::fs::remove_file(format!("/var/lib/archipelago/chromium-kiosk/{f}")).await;
+    }
+
     let republished = tokio::process::Command::new("/usr/bin/sudo")
         .args(["-n", "/usr/bin/avahi-set-host-name", hostname])
         .output()

image-recipe/configs/archipelago-kiosk-launcher.sh

@@ -106,6 +106,12 @@ fi
 ARCHIPELAGO_UID=$(id -u archipelago)
 
 while true; do
+    # A profile lock left by a previous boot encodes <hostname>-<pid>; after a
+    # hostname change (node rename) Chromium reads it as another computer
+    # holding the profile and refuses to start — with --noerrdialogs that is an
+    # invisible failure and the kiosk black-screens forever. Any Chromium that
+    # owned the lock is dead by now (pkill above / previous loop iteration).
+    rm -f /var/lib/archipelago/chromium-kiosk/Singleton{Lock,Cookie,Socket}
     # XDG_RUNTIME_DIR must be passed explicitly — without it Chromium's audio
     # backend can't find PipeWire-Pulse's socket at /run/user/<uid>/pulse/native,
     # falls back to raw ALSA "default", fails to connect, and produces no audio