[codex] fix RFC-011 follow-up regressions (#258)

* fix rfc-011 follow-up regressions

* test(cli): remove served schema-apply tests obsoleted by the cluster 409

This PR disables server-side schema apply for cluster-backed serving (409 →
`omnigraph cluster apply`). Two system_local tests still drove *served* schema
apply against a spawned `--cluster` server and asserted the pre-409 behavior, so
they failed under `cargo test --workspace`:

- `local_cli_schema_apply_enforces_engine_layer_policy` — expected a per-actor
  policy `denied`/allow on the served route; the route now 409s for everyone
  before policy runs.
- `local_cli_schema_apply_rejects_stored_query_breakage_before_publish` —
  expected a served apply to reject a stored-query breakage; the route now 409s
  before any apply.

Both exercise a path the PR intentionally removed. Their surviving coverage:
the 409 itself is pinned by `schema_routes::schema_apply_route_refuses_cluster_backed_server_mode`
(asserts 409 + no mutation); stored-query-breakage-before-publish stays covered
by `schema_routes::schema_apply_route_rejects_stored_query_breakage_before_publish`
(single-mode); engine-layer schema_apply Cedar enforcement stays covered by
`policy_engine_chassis`. Remove the obsolete served versions.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* fix(server): report the cluster-backed schema-apply 409 after the Cedar gate

The 409 ("schema apply is disabled for cluster-backed serving") fired at the top
of `server_schema_apply`, before `authorize_request`. An authenticated-but-
unauthorized actor therefore learned the server is cluster-backed (409) instead
of getting a normal 403 — leaking topology before authorization, against the
same posture that keeps `GET /graphs` default-deny.

Move the 409 below the Cedar gate so the route reports 401 → 403 → 409: an
unauthorized actor gets 403, and only an actor authorized for `schema_apply`
sees the actionable "use `omnigraph cluster apply`" 409. (An open/unauthenticated
server still 409s, as it has no topology to protect.)

Regression: `schema_apply_route_cluster_backed_denies_unauthorized_actor_before_409`
(POLICY_YAML grants no schema_apply → act-ragnor gets 403, not 409). Addresses the
bot-review finding on #258.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

crates/omnigraph-cli/src/scope.rs

@@ -186,9 +186,9 @@ fn scope_from_binding(
         ScopeBinding::Cluster(cluster) => {
             if capability == Capability::Any {
                 bail!(
-                    "{source} resolves a cluster scope, which is maintenance-only; run \
-                     data commands through a server, or use --store <uri> for ad-hoc \
-                     direct access"
+                    "{source} resolves a cluster scope, which is not valid for graph data \
+                     commands; run data commands through a server, or use --store <uri> \
+                     for ad-hoc direct access"
                 );
             }
             // A cluster value is a config name (resolved against `clusters:`)
@@ -501,7 +501,7 @@ mod tests {
         )
         .unwrap_err()
         .to_string();
-        assert!(err.contains("maintenance-only"), "{err}");
+        assert!(err.contains("not valid for graph data commands"), "{err}");
     }
 
     #[test]