fix(admin): clear session-expired flag on successful browser restart (0.53.1)

A successful `coordinated_restart` re-runs `on_launch`, which re-injects
PHPSESSID and re-probes via `verify_session_with_recircuit` — so reaching
`Ok(())` proves the session is live. But the handler never dropped the
sticky `session_expired` flag, so the admin UI continued to report
"Session Expired" and chapter workers kept idling until the operator
made a second click on "Clear expired" (or pushed a new cookie).

The fix is one line in `restart_browser`: on `Ok(())`, call
`c.session.clear_expired()`. The error path still leaves the flag set
since a failed restart means the probe didn't confirm.

Adds a focused `clear_expired_flips_sticky_flag_without_touching_session`
unit test to pin the controller-side semantic; the existing
`update_persists_and_clears_expired_then_round_trips` test continues to
cover the cookie-refresh path.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

backend/Cargo.lock

@@ -1470,7 +1470,7 @@ checksum = "c41e0c4fef86961ac6d6f8a82609f55f31b05e4fce149ac5710e439df7619ba4"
 
 [[package]]
 name = "mangalord"
-version = "0.53.0"
+version = "0.53.1"
 dependencies = [
  "anyhow",
  "argon2",

backend/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "mangalord"
-version = "0.53.0"
+version = "0.53.1"
 edition = "2021"
 default-run = "mangalord"
 

backend/src/api/admin/crawler.rs

@@ -233,6 +233,13 @@ async fn restart_browser(
 ) -> AppResult<Json<RestartResponse>> {
     let c = require_crawler(&state)?;
     let result = c.browser_manager.coordinated_restart(c.drain_deadline).await;
+    // A successful coordinated_restart re-runs on_launch, which re-injects
+    // PHPSESSID and re-probes — i.e. the session is live. Drop the sticky
+    // `session_expired` flag so chapter workers stop idling without
+    // requiring a second click on "Clear expired".
+    if result.is_ok() {
+        c.session.clear_expired();
+    }
     // Push the post-restart browser phase to live subscribers immediately.
     c.status.poke();
     repo::admin_audit::insert(

backend/src/crawler/session_control.rs

@@ -164,4 +164,17 @@ mod tests {
             Some("good-sid-123")
         );
     }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn clear_expired_flips_sticky_flag_without_touching_session(pool: PgPool) {
+        // The flag starts `true` per `controller(pool)`'s test wiring.
+        let c = controller(pool);
+        assert!(c.is_expired(), "test fixture starts with the flag set");
+        c.clear_expired();
+        assert!(!c.is_expired(), "clear_expired flips the sticky flag to false");
+        assert!(
+            c.current().await.is_none(),
+            "clear_expired does not invent a session"
+        );
+    }
 }

frontend/package.json

@@ -1,6 +1,6 @@
 {
   "name": "mangalord-frontend",
-  "version": "0.53.0",
+  "version": "0.53.1",
   "private": true,
   "type": "module",
   "scripts": {