Add TUI kanban board, review workflow, and new task statuses

Replace task statuses (pending/running/succeeded/failed/cancelled) with
a kanban workflow: todo → in_progress → in_review → done/wontdo.

When a non-review agent task completes, the API auto-creates a child
review task and moves the parent to in_review. Only humans can move
tasks from in_review to done/wontdo via the TUI.

New components:
- cmd/tui: bubbletea kanban board with $EDITOR integration
- POST /api/v1/tasks/{id}/complete: agent completion callback
- Operator --api-url flag for completion callbacks
- ProviderQueue sets tasks to in_progress on pickup
- AgentTask reconciler calls /complete on job finish

hack/kind/manifests/operator-deployment.yaml

@@ -22,6 +22,7 @@ spec:
           args:
             - --metrics-bind-address=:8080
             - --health-probe-bind-address=:8081
+            - --api-url=http://forgebot-api.forgebot.svc.cluster.local:8000
           ports:
             - containerPort: 8080
               name: metrics