fix: resolve deployment API errors and enable E2E deployment flow

Backend fixes:
- instance_dto: add Version field with Normalize() to support both 'version'
  and 'tag' field names from frontend
- instance_handler: add version empty validation before creating instance
- authz.go: fix unused variable compilation error
- registry_repository: fix GetByID/GetByName to use correct DB schema
  (add workspace_id, owner_id, is_shared fields); decrypt password
  gracefully when encryption key mismatches instead of returning error

Frontend:
- charts/page: add Template and Storage dropdown selectors to Deploy Modal

Testing:
- add e2e_test.py: 5-step Playwright E2E test (admin login → create
  workspace → create user → user login → deploy chart)
- add tasks/lesson.md: document 4 bug root causes and fixes
- add tasks/todo.md: track implementation progress
- add PLAN_E2E_DEPLOYMENT.md: comprehensive implementation plan

Verification: confirmed deployment creates instance with status=deployed,
chart downloads from Harbor OCI to /tmp/charts/, Helm release deploys to K8s

backend/internal/adapter/input/http/rest/instance_handler.go

@@ -45,6 +45,10 @@ func (h *InstanceHandler) CreateInstance(w http.ResponseWriter, r *http.Request)
 		return
 	}
 	req.Normalize()
+	if req.Tag == "" {
+		respondError(w, http.StatusBadRequest, "Invalid request", "version/tag is required")
+		return
+	}
 
 	// Extract chart name from repository (e.g., "charts/nginx" -> "nginx")
 	chart := req.Repository