feat(nodes): remote ingress via Traefik file provider

Remote replicas publish an ephemeral host port; the agent reports the
assigned binding back in the create_container result and the backend
renders a per-service file-provider config into TRAEFIK_DYNAMIC_DIR
pointing Traefik at the node's mesh IP + port. Routes are rewritten on
every remote reconcile and removed on teardown or local placement.

Also: RetireService retires remote leftovers when a service returns to
local placement; remove_container is idempotent agent-side; tombstoned
replicas skip remove dispatch; the domains-stay-local ceiling is gone.

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

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

app/backend/internal/database/sqlcdb/querier.go

@@ -98,6 +98,8 @@ type Querier interface {
 	ListSchedulableAgents(ctx context.Context) ([]ListSchedulableAgentsRow, error)
 	// Only agents carrying every required placement tag (jsonb array containment).
 	ListSchedulableAgentsMatching(ctx context.Context, dollar_1 json.RawMessage) ([]ListSchedulableAgentsMatchingRow, error)
+	// Distinct agents holding inventory rows for a service.
+	ListServiceAgents(ctx context.Context, serviceID string) ([]string, error)
 	ListServiceContainers(ctx context.Context, serviceID string) ([]ListServiceContainersRow, error)
 	ListServiceTemplatesByCategoryForUser(ctx context.Context, arg ListServiceTemplatesByCategoryForUserParams) ([]ServiceTemplate, error)
 	ListServiceTemplatesForUser(ctx context.Context, ownerID uuid.NullUUID) ([]ServiceTemplate, error)
@@ -134,6 +136,9 @@ type Querier interface {
 	UpdateAgentHeartbeat(ctx context.Context, arg UpdateAgentHeartbeatParams) error
 	UpdateBackupTargetByIDAndUser(ctx context.Context, arg UpdateBackupTargetByIDAndUserParams) error
 	UpdateBanner(ctx context.Context, arg UpdateBannerParams) (Banner, error)
+	// Agent reports the real host bindings after create — persist them with
+	// the status flip so ingress can route to the assigned port.
+	UpdateContainerPorts(ctx context.Context, arg UpdateContainerPortsParams) error
 	UpdateContainerStatus(ctx context.Context, arg UpdateContainerStatusParams) error
 	UpdateDatabaseServiceNameAndPlanByIDAndUser(ctx context.Context, arg UpdateDatabaseServiceNameAndPlanByIDAndUserParams) error
 	UpdateDatabaseServiceNameByIDAndUser(ctx context.Context, arg UpdateDatabaseServiceNameByIDAndUserParams) error