Add global recent-deployments feed for the projects dashboard

The RECENT DEPLOYMENTS section queried the builds table, so
image-sourced services — which deploy without building — never
appeared and the dashboard reported "no deployments yet" while
containers were running.

- GET /api/v1/deployments lists latest deployments across the
  caller's services, joined with service + project names, ordered
  newest-first with a bounded limit
- ProjectsPage consumes it via listRecentDeployments; the DEPLOYS
  stat card now counts real deployments
- is_admin is now projected in register/upsert user responses, and
  the Better Auth mirror grants admin to the first mirrored account
  (previously only the legacy register path did)

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

docs/api/openapi.yaml

@@ -595,6 +595,56 @@ paths:
               schema:
                 $ref: '#/components/schemas/Deployment'
 
+  /deployments:
+    get:
+      tags:
+        - Deployments
+      summary: List recent deployments
+      description: Latest deployments across all services owned by the caller — feeds the dashboard deploy feed
+      security:
+        - bearerAuth: []
+      parameters:
+        - name: limit
+          in: query
+          required: false
+          schema:
+            type: integer
+            default: 10
+            maximum: 50
+      responses:
+        '200':
+          description: Recent deployments
+          content:
+            application/json:
+              schema:
+                type: object
+                properties:
+                  deployments:
+                    type: array
+                    items:
+                      type: object
+                      properties:
+                        id:
+                          type: string
+                        service_id:
+                          type: string
+                        service_name:
+                          type: string
+                        project_name:
+                          type: string
+                        status:
+                          type: string
+                        image_name:
+                          type: string
+                        started_at:
+                          type: string
+                          nullable: true
+                        completed_at:
+                          type: string
+                          nullable: true
+                        created_at:
+                          type: string
+
   /deployments/{id}:
     get:
       tags: