Continue web refactor work.

src/cthulhu/scripts/toolkits/Chromium/script.py

@@ -39,6 +39,7 @@ from cthulhu.ax_object import AXObject
 from cthulhu.ax_utilities import AXUtilities
 from cthulhu.scripts import default
 from cthulhu.scripts import web
+from cthulhu.scripts.web.event_router import RouteResult
 from .braille_generator import BrailleGenerator
 from .script_utilities import Utilities
 from .speech_generator import SpeechGenerator
@@ -152,12 +153,20 @@ class Script(web.Script):
     def onCheckedChanged(self, event):
         """Callback for object:state-changed:checked accessibility events."""
 
-        if super().onCheckedChanged(event):
-            return
+        def handle_shared_web(routed_event: object) -> RouteResult:
+            handled = web.Script.onCheckedChanged(self, routed_event)
+            return RouteResult.HANDLED if handled else RouteResult.CONTINUE
 
-        msg = "CHROMIUM: Passing along event to default script"
-        debug.printMessage(debug.LEVEL_INFO, msg, True)
-        default.Script.onCheckedChanged(self, event)
+        self._eventRouter.route_event(
+            event,
+            application_handler=None,
+            toolkit_handler=None,
+            web_handler=handle_shared_web,
+            default_handler=lambda routed_event: default.Script.onCheckedChanged(
+                self,
+                routed_event,
+            ),
+        )
 
     def onColumnReordered(self, event):
         """Callback for object:column-reordered accessibility events."""

src/cthulhu/scripts/toolkits/Gecko/script.py

@@ -42,6 +42,7 @@ from cthulhu.ax_object import AXObject
 from cthulhu.ax_utilities import AXUtilities
 from cthulhu.scripts import default
 from cthulhu.scripts import web
+from cthulhu.scripts.web.event_router import RouteResult
 from .script_utilities import Utilities
 
 
@@ -125,12 +126,20 @@ class Script(web.Script):
     def onCheckedChanged(self, event):
         """Callback for object:state-changed:checked accessibility events."""
 
-        if super().onCheckedChanged(event):
-            return
+        def handle_shared_web(routed_event: object) -> RouteResult:
+            handled = web.Script.onCheckedChanged(self, routed_event)
+            return RouteResult.HANDLED if handled else RouteResult.CONTINUE
 
-        msg = "GECKO: Passing along event to default script"
-        debug.printMessage(debug.LEVEL_INFO, msg, True)
-        default.Script.onCheckedChanged(self, event)
+        self._eventRouter.route_event(
+            event,
+            application_handler=None,
+            toolkit_handler=None,
+            web_handler=handle_shared_web,
+            default_handler=lambda routed_event: default.Script.onCheckedChanged(
+                self,
+                routed_event,
+            ),
+        )
 
     def onColumnReordered(self, event):
         """Callback for object:column-reordered accessibility events."""

src/cthulhu/scripts/web/event_router.py

@@ -0,0 +1,121 @@
+#!/usr/bin/env python3
+#
+# Copyright (c) 2026 Stormux
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the
+# Free Software Foundation, Inc., Franklin Street, Fifth Floor,
+# Boston MA  02110-1301 USA.
+
+"""Defines the ownership contract for routing web accessibility events.
+
+Handlers run in application, toolkit, and shared-web order. A handler returns
+``HANDLED`` to claim the event, ``CONTINUE`` to offer it to the next layer, or
+``DEFER_DEFAULT`` to skip directly to the default script. Invalid results and
+handler exceptions fail safely by reaching the default handler exactly once.
+
+This module defines the Phase 2 routing boundary. Existing event families must
+be migrated individually; creating a router does not activate parallel routing.
+"""
+
+from __future__ import annotations
+
+import enum
+from collections.abc import Callable
+
+from cthulhu import debug
+
+
+class RouteResult(enum.Enum):
+    """A routing layer's explicit decision for one accessibility event."""
+
+    HANDLED = enum.auto()
+    CONTINUE = enum.auto()
+    DEFER_DEFAULT = enum.auto()
+
+
+class RoutingLayer(enum.Enum):
+    """The layer which ultimately owns an accessibility event."""
+
+    APPLICATION = enum.auto()
+    TOOLKIT = enum.auto()
+    SHARED_WEB = enum.auto()
+    DEFAULT = enum.auto()
+
+
+RouteHandler = Callable[[object], RouteResult]
+DefaultHandler = Callable[[object], object]
+
+
+class WebEventRouter:
+    """Routes one event to at most one owning presentation layer."""
+
+    def route_event(
+        self,
+        event: object,
+        *,
+        application_handler: RouteHandler | None,
+        toolkit_handler: RouteHandler | None,
+        web_handler: RouteHandler | None,
+        default_handler: DefaultHandler,
+    ) -> RoutingLayer:
+        """Route ``event`` in application-first order and return its owner."""
+
+        handlers = (
+            (RoutingLayer.APPLICATION, application_handler),
+            (RoutingLayer.TOOLKIT, toolkit_handler),
+            (RoutingLayer.SHARED_WEB, web_handler),
+        )
+        for layer, handler in handlers:
+            if handler is None:
+                continue
+
+            try:
+                result = handler(event)
+            except Exception as error:  # pylint: disable=broad-except
+                message = (
+                    f"WEB EVENT ROUTER: {layer.name} raised "
+                    f"{type(error).__name__}; deferring to DEFAULT"
+                )
+                debug.printMessage(debug.LEVEL_WARNING, message, True)
+                return self._route_to_default(event, default_handler)
+
+            if not isinstance(result, RouteResult):
+                message = (
+                    f"WEB EVENT ROUTER: {layer.name} returned invalid result "
+                    f"{type(result).__name__}; deferring to DEFAULT"
+                )
+                debug.printMessage(debug.LEVEL_WARNING, message, True)
+                return self._route_to_default(event, default_handler)
+
+            message = f"WEB EVENT ROUTER: {layer.name} -> {result.name}"
+            debug.printMessage(debug.LEVEL_INFO, message, True)
+            if result is RouteResult.HANDLED:
+                return layer
+            if result is RouteResult.DEFER_DEFAULT:
+                return self._route_to_default(event, default_handler)
+
+        return self._route_to_default(event, default_handler)
+
+    @staticmethod
+    def _route_to_default(
+        event: object,
+        default_handler: DefaultHandler,
+    ) -> RoutingLayer:
+        debug.printMessage(
+            debug.LEVEL_INFO,
+            "WEB EVENT ROUTER: DEFAULT -> HANDLED",
+            True,
+        )
+        default_handler(event)
+        return RoutingLayer.DEFAULT

src/cthulhu/scripts/web/meson.build

@@ -2,6 +2,7 @@ web_python_sources = files([
   '__init__.py',
   'bookmarks.py',
   'braille_generator.py',
+  'event_router.py',
   'script.py',
   'script_utilities.py',
   'sound_generator.py',
@@ -12,4 +13,4 @@ web_python_sources = files([
 python3.install_sources(
   web_python_sources,
   subdir: 'cthulhu/scripts/web'
-)
+)

src/cthulhu/scripts/web/script.py

@@ -64,6 +64,7 @@ from cthulhu.ax_utilities_event import AXUtilitiesEvent, TextEventReason
 
 from .bookmarks import Bookmarks
 from .braille_generator import BrailleGenerator
+from .event_router import WebEventRouter
 from .sound_generator import SoundGenerator
 from .speech_generator import SpeechGenerator
 from .tutorial_generator import TutorialGenerator
@@ -80,6 +81,8 @@ def _log_tokens(tokens, reason=None, timestamp=True, stack=False):
 
 class Script(default.Script):
 
+    _eventRouter = WebEventRouter()
+
     def __init__(self, app):
         super().__init__(app)