fix(state): jangan bangun mention index di mode attach

AppStateRest::new() men-spawn thread ignore::Walk untuk mention_index
tanpa syarat, padahal mode --attach cuma dipakai untuk render lokal —
handle_key dan logika mention berjalan di sisi daemon lewat IPC, jadi
index di client attach tidak pernah dipakai. Ini bikin setiap
--attach melakukan full workspace walk (sampai 50.000 entry) sia-sia.

Pindahkan thread-spawn itu ke method terpisah
spawn_mention_index_build(), dipanggil eksplisit dari
run_single_process() dan run_daemon() setelah AppStateRest::new(),
tapi sengaja tidak dipanggil dari run_attach().

src/app/state/rest.rs

@@ -206,23 +206,35 @@ impl AppStateRest {
             });
         }
 
-        // Fire-and-forget background file index build for `@file` mention
+        state
-        // autocomplete.
+    }
-        //
+
-        // Flow: spawn OS thread -> `ignore::Walk` each workspace root,
+    /// Spawn the background thread that walks every workspace root and
-        // collecting file paths (workspace-index-prefixed for roots beyond
+    /// populates `mention_index` for `@file` mention autocomplete.
-        // the first, matching `resolve_path`'s `[N]path` convention) -> stop
+    ///
-        // once 50,000 entries are collected -> store the result in
+    /// Why a separate method, not called from `new()`: the attach-only
-        // `mention_index`.
+    /// TUI client also constructs an `AppStateRest` (for local rendering
-        //
+    /// state) but never runs tools or `handle_key` locally — it forwards
-        // Why a raw thread and not a background tokio task: there is no
+    /// keystrokes to the daemon over IPC, which has its own `AppStateRest`
-        // persistent async runtime driving the render loop, and this is
+    /// with its own index. Spawning this walk in the attach client would
-        // blocking filesystem I/O -- a dedicated thread keeps startup
+    /// waste a full workspace scan for an index nothing there consumes.
-        // non-blocking. Not joined, same rationale as the LSP provisioning
+    /// Callers that DO need the index (single-process mode, the daemon)
-        // thread above: a slow/huge repo must not delay the TUI appearing.
+    /// call this explicitly after construction.
-        {
+    ///
-            let mention_index = state.mention_index.clone();
+    /// Flow: spawn OS thread -> `ignore::Walk` each workspace root,
-            let roots = state.workspace_roots.clone();
+    /// collecting file paths (workspace-index-prefixed for roots beyond
+    /// the first, matching `resolve_path`'s `[N]path` convention) -> stop
+    /// once 50,000 entries are collected -> store the result in
+    /// `mention_index`.
+    ///
+    /// Why a raw thread and not a background tokio task: there is no
+    /// persistent async runtime driving the render loop, and this is
+    /// blocking filesystem I/O -- a dedicated thread keeps startup
+    /// non-blocking. Not joined, same rationale as the LSP provisioning
+    /// thread above: a slow/huge repo must not delay the TUI appearing.
+    pub fn spawn_mention_index_build(&self) {
+        let mention_index = self.mention_index.clone();
+        let roots = self.workspace_roots.clone();
         std::thread::spawn(move || {
             const MAX_MENTION_ENTRIES: usize = 50_000;
             let mut paths = Vec::new();
@@ -244,9 +256,6 @@ impl AppStateRest {
         });
     }
 
-        state
-    }
-
     /// Whether an agent turn is currently running.
     ///
     /// Return: `false` (and logs a warning) if the mutex is poisoned, rather

src/main.rs

@@ -109,6 +109,7 @@ fn run_single_process() -> Result<()> {
         &session_dir,
         store.memory_dir,
     );
+    state.spawn_mention_index_build();
     state.sessions = model::session::Session::list(&store.base_dir);
 
 
@@ -442,6 +443,7 @@ fn run_daemon() -> Result<()> {
         &session_dir,
         store.memory_dir,
     );
+    state.spawn_mention_index_build();
     state.sessions = model::session::Session::list(&store.base_dir);
 
     let _rt = tokio::runtime::Runtime::new()?;