feat: outbound webhooks — signed event delivery + delivery log

Every audited action now emits a "resource.action" event (bare actions
get resource-qualified; already-qualified actions like service.clone
pass through). Webhooks subscribe per-user with exact names, resource.*
wildcards, or *.

- schema: outbound_webhooks + webhook_deliveries (sqlc + goose)
- dispatcher: 4 workers, 512-queue, 3 attempts with backoff, 10s timeout;
  deliveries record status/http-code/body(4KiB)/duration
- signing: X-Containr-Signature sha256=<hmac> over raw body;
  X-Containr-Event + X-Containr-Delivery headers; custom headers per hook
- api: CRUD + /deliveries + /test (ping) under authed group
- fix: SetAuditDB never called — LogAudit was a silent no-op at every
  call site; now wired at boot
- coverage: service create/delete audited (previously uninstrumented)
- cli: containr webhooks list|create|update|delete|deliveries|test
- mcp: 6 tools, delete requires confirm
- frontend: /settings/webhooks page — list/create/expand-deliveries/
  test/disable/delete, secret-shown-once banner; nav + account menu
- openapi + regenerated types; CLI.md + docs snapshot; roadmap ticks

app/backend/internal/api/services.go

@@ -454,6 +454,10 @@ func handleCreateService(c *gin.Context) {
 	}
 	service.Domains = loadServiceDomains(db.(*database.DB), service.ID)
 
+	LogAuditWithRequest(c, "service", service.ID.String(), "create", map[string]interface{}{
+		"name": service.Name, "type": service.Type, "project_id": service.ProjectID,
+	})
+
 	c.JSON(http.StatusCreated, gin.H{"service": service})
 }
 
@@ -876,5 +880,7 @@ func handleDeleteService(c *gin.Context) {
 		return
 	}
 
+	LogAuditWithRequest(c, "service", serviceID.String(), "delete", map[string]interface{}{})
+
 	c.JSON(http.StatusOK, gin.H{"message": "Service deleted successfully"})
 }