feat: enable UI actions from AI chat

proto/gen/rill/runtime/v1/runtime.swagger.yaml

@@ -436,6 +436,9 @@ paths:
                 description: |-
                   Optional context for prompts handled by the feedback_agent.
                   The field is ignored if another agent is selected.
+              uiContext:
+                $ref: '#/definitions/v1UIContext'
+                description: Optional browser UI context. Only actions explicitly marked with data-ai-action are included.
             title: Request message for RuntimeService.Complete
       tags:
         - RuntimeService
@@ -496,6 +499,9 @@ paths:
                 description: |-
                   Optional context for prompts handled by the feedback_agent.
                   The field is ignored if another agent is selected.
+              uiContext:
+                $ref: '#/definitions/v1UIContext'
+                description: Optional browser UI context. Only actions explicitly marked with data-ai-action are included.
             title: Request message for RuntimeService.CompleteStreaming
       tags:
         - RuntimeService
@@ -8449,6 +8455,29 @@ definitions:
           type: object
           $ref: '#/definitions/v1Span'
     description: Trace contains trace spans captured during request execution. Used both in successful responses and as gRPC error details when trace=true and the request fails.
+  v1UIAction:
+    type: object
+    properties:
+      id:
+        type: string
+        description: Stable identifier from the element's data-ai-action attribute.
+      label:
+        type: string
+        description: Human-readable accessible label for the action.
+    description: A non-destructive UI action explicitly exposed to the AI by the browser.
+  v1UIContext:
+    type: object
+    properties:
+      pagePath:
+        type: string
+        description: Current browser path. The origin is intentionally omitted.
+      actions:
+        type: array
+        items:
+          type: object
+          $ref: '#/definitions/v1UIAction'
+        description: Visible, enabled, uniquely-addressable actions on the page.
+    description: Context about safe actions available on the user's current page.
   v1UnpackEmptyResponse:
     type: object
     title: Response message for RuntimeService.UnpackEmpty