fix: decouple oneliner-heal from request handler tasks

heal_orphans_if_idle called regenerate_missing_oneliners_for_user
inline on the request task, blocking the browser for up to N×60s
when orphans existed (observed with 16 cases after manual cleanup).

Now: CAS on new OnelinerHealBusy flag + tokio::spawn + BusyGuard
reset-on-drop. Handler returns immediately; the existing
OnelinerUpdated SSE event delivers results via the usual reload.
Startup recovery shares the flag so a concurrent page-load during
boot cannot fire a parallel regen loop against Ollama.

Regression test uses wiremock + timeout(150ms) + .expect(5) to
verify both non-blocking return and dedup of parallel invocations.

server/src/lib.rs

@@ -38,6 +38,12 @@ pub type WorkerBusy = Arc<AtomicBool>;
 pub struct AnalyzeBusy(pub WorkerBusy);
 #[derive(Clone)]
 pub struct TranscribeBusy(pub WorkerBusy);
+/// Dedup flag for the detached oneliner-heal `tokio::spawn` fired from
+/// `heal_orphans_if_idle`. The handler CAS's this to `true`; the spawned
+/// task resets via [`BusyGuard`] on drop. Keeps concurrent page-loads
+/// from launching parallel Ollama-call loops against the same data.
+#[derive(Clone)]
+pub struct OnelinerHealBusy(pub WorkerBusy);
 
 /// RAII guard that flips a [`WorkerBusy`] true on construction and false on
 /// drop — panic-safe. Shared across analyze + transcribe workers.
@@ -68,6 +74,7 @@ pub struct PipelineState {
     pub analyze_tx: AnalyzeSender,
     pub transcribe_busy: TranscribeBusy,
     pub transcribe_tx: TranscribeSender,
+    pub oneliner_heal_busy: OnelinerHealBusy,
 }
 
 /// Shared application state. Clonable — all fields are cheap to clone
@@ -81,6 +88,7 @@ pub struct AppState {
     pub magic_link_store: MagicLinkStore,
     pub analyze_busy: AnalyzeBusy,
     pub transcribe_busy: TranscribeBusy,
+    pub oneliner_heal_busy: OnelinerHealBusy,
     pub events_tx: events::EventSender,
     pub http_client: reqwest::Client,
     pub vocab: Arc<Gazetteer>,
@@ -128,6 +136,12 @@ impl FromRef<AppState> for TranscribeBusy {
     }
 }
 
+impl FromRef<AppState> for OnelinerHealBusy {
+    fn from_ref(state: &AppState) -> Self {
+        state.oneliner_heal_busy.clone()
+    }
+}
+
 impl FromRef<AppState> for PipelineState {
     fn from_ref(state: &AppState) -> Self {
         PipelineState {
@@ -135,6 +149,7 @@ impl FromRef<AppState> for PipelineState {
             analyze_tx: state.analyze_tx.clone(),
             transcribe_busy: state.transcribe_busy.clone(),
             transcribe_tx: state.transcribe_tx.clone(),
+            oneliner_heal_busy: state.oneliner_heal_busy.clone(),
         }
     }
 }
@@ -171,6 +186,7 @@ pub fn create_router(config: Arc<Config>) -> Router {
         magic_link_store: magic_link::new_store(),
         analyze_busy: AnalyzeBusy(Arc::new(AtomicBool::new(false))),
         transcribe_busy: TranscribeBusy(Arc::new(AtomicBool::new(false))),
+        oneliner_heal_busy: OnelinerHealBusy(Arc::new(AtomicBool::new(false))),
         events_tx: events::channel(),
         http_client: reqwest::Client::new(),
         vocab: Arc::new(Gazetteer::empty()),