feat(ECR-042): OpsCMS FeedSlot 薄写面

Admin POST/PUT 复用 admin.cms.write；C 端 GET /home/feed-slots；首页无 active 槽隐藏推荐区、失败回退展示；无新 migration。

Co-authored-by: Cursor <cursoragent@cursor.com>

proto/openapi.yaml

@@ -841,6 +841,19 @@ paths:
           description: Unauthorized
         '403':
           description: Forbidden
+    post:
+      tags: [admin]
+      summary: Create FeedSlot
+      description: Requires admin.cms.write · ECR-042
+      responses:
+        '200':
+          description: OK
+        '400':
+          description: Invalid
+        '403':
+          description: Forbidden
+        '409':
+          description: Conflict
 
   /api/v1/admin/cms/feed-slots/{id}:
     get:
@@ -856,6 +869,26 @@ paths:
           description: OK
         '404':
           description: Not found
+    put:
+      tags: [admin]
+      summary: Update FeedSlot
+      description: Requires admin.cms.write · deactivate via active=false
+      parameters:
+        - in: path
+          name: id
+          required: true
+          schema: { type: string, format: uuid }
+      responses:
+        '200':
+          description: OK
+        '400':
+          description: Invalid
+        '403':
+          description: Forbidden
+        '404':
+          description: Not found
+        '409':
+          description: Conflict
 
   /api/v1/admin/cms/publications:
     get:
@@ -1495,6 +1528,18 @@ paths:
         '200':
           description: OK
 
+  /api/v1/home/feed-slots:
+    get:
+      tags: [system]
+      summary: Homepage active feed slots (ECR-042)
+      parameters:
+        - in: query
+          name: placement
+          schema: { type: string, default: home, enum: [home, explore, ask] }
+      responses:
+        '200':
+          description: OK
+
   /api/v1/home/daily-tips:
     get:
       tags: [system]