feat(container): add current container metrics view

Expose a dedicated container metrics endpoint and surface current CPU, memory, and root filesystem usage in the bot container view. This gives operators a quick health snapshot while degrading cleanly on unsupported backends.

spec/swagger.yaml

@@ -1486,6 +1486,17 @@ definitions:
       user_config_schema:
         $ref: '#/definitions/channel.ConfigSchema'
     type: object
+  handlers.ContainerCPUMetricsResponse:
+    properties:
+      kernel_nanoseconds:
+        type: integer
+      usage_nanoseconds:
+        type: integer
+      usage_percent:
+        type: number
+      user_nanoseconds:
+        type: integer
+    type: object
   handlers.ContainerGPURequest:
     properties:
       devices:
@@ -1493,6 +1504,38 @@ definitions:
           type: string
         type: array
     type: object
+  handlers.ContainerMemoryMetricsResponse:
+    properties:
+      limit_bytes:
+        type: integer
+      usage_bytes:
+        type: integer
+      usage_percent:
+        type: number
+    type: object
+  handlers.ContainerMetricsPayloadResponse:
+    properties:
+      cpu:
+        $ref: '#/definitions/handlers.ContainerCPUMetricsResponse'
+      memory:
+        $ref: '#/definitions/handlers.ContainerMemoryMetricsResponse'
+      storage:
+        $ref: '#/definitions/handlers.ContainerStorageMetricsResponse'
+    type: object
+  handlers.ContainerMetricsStatusResponse:
+    properties:
+      exists:
+        type: boolean
+      task_running:
+        type: boolean
+    type: object
+  handlers.ContainerStorageMetricsResponse:
+    properties:
+      path:
+        type: string
+      used_bytes:
+        type: integer
+    type: object
   handlers.ContextUsage:
     properties:
       context_window:
@@ -1638,6 +1681,21 @@ definitions:
       path:
         type: string
     type: object
+  handlers.GetContainerMetricsResponse:
+    properties:
+      backend:
+        type: string
+      metrics:
+        $ref: '#/definitions/handlers.ContainerMetricsPayloadResponse'
+      sampled_at:
+        type: string
+      status:
+        $ref: '#/definitions/handlers.ContainerMetricsStatusResponse'
+      supported:
+        type: boolean
+      unsupported_reason:
+        type: string
+    type: object
   handlers.GetContainerResponse:
     properties:
       cdi_devices:
@@ -4037,6 +4095,26 @@ paths:
       summary: Write text content to a file
       tags:
       - containerd
+  /bots/{bot_id}/container/metrics:
+    get:
+      parameters:
+      - description: Bot ID
+        in: path
+        name: bot_id
+        required: true
+        type: string
+      responses:
+        "200":
+          description: OK
+          schema:
+            $ref: '#/definitions/handlers.GetContainerMetricsResponse'
+        "500":
+          description: Internal Server Error
+          schema:
+            $ref: '#/definitions/handlers.ErrorResponse'
+      summary: Get current container metrics for bot
+      tags:
+      - containerd
   /bots/{bot_id}/container/skills:
     delete:
       parameters: