feat: add immediate context compaction API, UI button, and /compact slash command

- Add POST /bots/:bot_id/sessions/:session_id/compact endpoint for
  synchronous context compaction with fallback to chat model when no
  dedicated compaction model is configured
- Add "Compact Now" button to session info panel in the web UI
- Add /compact slash command for triggering compaction from chat
- Regenerate OpenAPI spec and TypeScript SDK

spec/swagger.yaml

@@ -1780,6 +1780,15 @@ definitions:
           $ref: '#/definitions/handlers.DailyTokenUsage'
         type: array
     type: object
+  handlers.TriggerCompactResponse:
+    properties:
+      message_count:
+        type: integer
+      status:
+        type: string
+      summary:
+        type: string
+    type: object
   handlers.createSessionRequest:
     properties:
       channel_type:
@@ -2659,8 +2668,6 @@ definitions:
         type: integer
       compaction_threshold:
         type: integer
-      context_token_budget:
-        type: integer
       discuss_probe_model_id:
         type: string
       heartbeat_enabled:
@@ -2706,8 +2713,6 @@ definitions:
         type: integer
       compaction_threshold:
         type: integer
-      context_token_budget:
-        type: integer
       discuss_probe_model_id:
         type: string
       heartbeat_enabled:
@@ -5766,6 +5771,36 @@ paths:
       summary: Update a session
       tags:
       - sessions
+  /bots/{bot_id}/sessions/{session_id}/compact:
+    post:
+      description: Run context compaction synchronously for a session
+      parameters:
+      - description: Bot ID
+        in: path
+        name: bot_id
+        required: true
+        type: string
+      - description: Session ID
+        in: path
+        name: session_id
+        required: true
+        type: string
+      responses:
+        "200":
+          description: OK
+          schema:
+            $ref: '#/definitions/handlers.TriggerCompactResponse'
+        "400":
+          description: Bad Request
+          schema:
+            $ref: '#/definitions/handlers.ErrorResponse'
+        "500":
+          description: Internal Server Error
+          schema:
+            $ref: '#/definitions/handlers.ErrorResponse'
+      summary: Trigger immediate context compaction
+      tags:
+      - compaction
   /bots/{bot_id}/sessions/{session_id}/status:
     get:
       description: Get aggregated info for a chat session including message count,