Hooks: dispatch HOOK messages directly, bypassing state.messages

The previous fix routed (MSG,HOOK:...) lines through state.messages
and then immediately ack'd them to suppress the user-visible popup.
But state changes are debounced 0.25s before listeners fire, so the
HOOK message was already ack'd (removed from the list) by the time
Hooks._on_state_change saw the update - and the hook never ran.

Add Hooks.dispatch_hook_message() as a direct entry point and call
it from Planner._add_message. HOOK lines are dispatched synchronously
from the planner thread; the user message list is left untouched, so
no popup leaks and no debounce race.

src/py/bbctrl/Hooks.py

@@ -249,6 +249,23 @@ class Hooks:
 
     # -- Hook execution --
 
+    def dispatch_hook_message(self, text):
+        """Direct entry point for HOOK:<event>:<data> messages emitted
+        by the planner via (MSG,HOOK:...) comments. Bypasses the
+        state.messages list (which the UI also reads), so callers can
+        suppress popup display without losing the hook dispatch.
+
+        Returns True if the text matched a HOOK: line and was
+        dispatched, False otherwise."""
+        if not isinstance(text, str) or not text.startswith('HOOK:'):
+            return False
+        parts = text[5:].split(':', 1)
+        event = parts[0]
+        data = parts[1] if len(parts) > 1 else ''
+        self._fire('custom', {'event': event, 'data': data},
+                   custom_name=event)
+        return True
+
     def register_internal(self, name, fn, block_unpause=True,
                           auto_resume=True, timeout=120):
         """Register an in-process handler for HOOK:<name> events.

src/py/bbctrl/Planner.py

@@ -196,25 +196,19 @@ class Planner():
 
 
     def _add_message(self, text):
-        # HOOK:<event>:<data> messages are an internal IPC channel
-        # between the gcode preprocessor and Hooks; they should not
-        # surface as user-visible message popups. Hooks._on_state_change
-        # will still see them via the messages list before we filter.
         line = self.ctrl.state.get('line', 0)
         if 0 <= line: where = '%s:%d' % (self.where, line)
         else: where = self.where
 
-        if isinstance(text, str) and text.startswith('HOOK:'):
-            # Push it through state.messages so Hooks._on_state_change
-            # can see and dispatch it, then immediately ack it so the UI
-            # doesn't render a popup.
-            self.ctrl.state.add_message(text)
-            try:
-                msgs = self.ctrl.state.get('messages', []) or []
-                if msgs:
-                    self.ctrl.state.ack_message(msgs[-1].get('id', -1))
-            except Exception:
-                pass
+        # HOOK:<event>:<data> messages are an internal IPC channel
+        # between the gcode preprocessor and Hooks; bypass the user
+        # message list so they don't surface as popups, and dispatch
+        # the hook directly. Routing through state.messages would
+        # only deliver it after the 0.25s state-change debounce, by
+        # which point we'd have to keep it visible to ensure Hooks
+        # could see it.
+        hooks = getattr(self.ctrl, 'hooks', None)
+        if hooks is not None and hooks.dispatch_hook_message(text):
             self.log.info('HOOK msg: %s' % text, where = where)
             return