fix: harden mode acceptance startup

Give the daemon its normal five-second handshake window before switching
the mode-system acceptance client to short frame polling. Document reload
and session-persistence boundaries and correct stale describe-key guidance.

docs/mode-system-wiring-framing.md

@@ -316,6 +316,9 @@ silently change an existing API unrelated to describe-key.
    views. The hidden-buffer (registry-only) gap is pre-existing: those
    buffers receive neither language detection nor syntax attachment and
    need their own fix.
+   An explicit nil clear is persistent across switches, not across a future
+   reload path that deliberately fires `buffer.after-load`; reload re-detects
+   the language just like a fresh open.
 4. **GPU optimistic-edit bypass is a non-issue for mode-scoped
    bindings** — the GPU frontend optimistically inserts plain printable
    characters (outside `BUILTIN_PAIR_CHARS`) and Tab without round-tripping
@@ -342,6 +345,10 @@ silently change an existing API unrelated to describe-key.
   side-quest (`side-quest-backlog.md:43`). This framing just wires the
   mechanism; modeline detection can override the initialized mode via
   `pmacs.buffer.set_major_mode` when it lands.
+- **Explicit-mode session persistence** — desktop restore reopens files and
+  recovers detected modes through `buffer.after-load`, but explicit overrides
+  and clears are not serialized. Design that with session/settings persistence,
+  not as hidden state in this wiring layer.
 - **Mode help display** (`describe-mode`) — straightforward once the mode
   is stored, but not table-stakes for wiring.
 

src/editor.rs

@@ -8552,9 +8552,9 @@ mod tests {
 
     /// T M5.6f: `M-x editor.describe-instance-buffer` switches the
     /// active window to *pmacs-instance* and binds buffer-local `q`
-    /// to `buffer.kill-this`. The buffer-local binding is verified by
-    /// resolving directly against the keymap stack — `pmacs.describe.key`
-    /// only consults global scope.
+    /// to `buffer.kill-this`. Resolve directly against the keymap stack
+    /// to pin the exact buffer-local scope independently of the Lua
+    /// describe-key rendering surface.
     #[test]
     fn editor_describe_instance_buffer_switches_and_binds_q() {
         let mut state = EditorState::new();

tests/mode_system_wiring_acceptance.rs

@@ -71,8 +71,8 @@ impl Grid {
 fn attach(daemon: &TestDaemon) -> (Client, Grid) {
     let mut stream = daemon.connect();
     stream
-        .set_read_timeout(Some(Duration::from_millis(100)))
-        .expect("set daemon read timeout");
+        .set_read_timeout(Some(Duration::from_secs(5)))
+        .expect("set daemon handshake timeout");
     let hello: Hello = read_message(&mut stream).expect("read daemon Hello");
     assert_eq!(hello.protocol_version, PROTOCOL_VERSION);
     write_message(
@@ -84,6 +84,9 @@ fn attach(daemon: &TestDaemon) -> (Client, Grid) {
         },
     )
     .expect("attach grid frontend");
+    stream
+        .set_read_timeout(Some(Duration::from_millis(100)))
+        .expect("set daemon frame timeout");
 
     let deadline = Instant::now() + Duration::from_secs(5);
     let mut grid = Grid::new();