Unify the Tenant CRD with enterprise-api -provision-tenant (lightweight)

Closes a gap named across CLAUDE.md/docs/architecture.md/deploy/README.md
since early Phase 4: the operator's Tenant CRD and -provision-tenant
were two disconnected mechanisms. The operator's reconciler generated a
K8s Secret with a locally-generated random password that authenticated
against nothing (nothing ever called ClickHouse to create a matching
user), and unconditionally claimed status.phase=Active the moment a
Tenant object existed -- actively misleading, not just incomplete.

Two unification shapes were considered (surfaced to the user via
AskUserQuestion, given the real difference in blast radius): the
operator's reconcile loop becoming a second real actor (new Postgres +
ClickHouse admin credentials flowing into the K8s controller, plus real
reconcile-loop idempotency/retry design for an inherently one-shot
external side effect), or keeping -provision-tenant as the sole real
actor and having it also sync its result into the CRD. Went with the
lighter option.

enterprise/internal/tenantcrd (new): a Syncer using the K8s dynamic
client (unstructured.Unstructured + a GroupVersionResource, not
deploy/operator's typed Tenant struct -- avoids a cross-module Go
dependency between two independently-versioned modules for one type).
Upserts the Tenant object, creates/updates a Secret with the *real*
ClickHouse credentials owned by that Tenant via an OwnerReference, then
patches status.{clickHouseDatabaseName,clickHouseSecretRef,
tantivyIndexPath}. Idempotent and safe to retry: never rotates a
credential across a re-sync, never overwrites a pre-existing
spec.displayName a human/GitOps process set.

cmd/enterprise-api/main.go's runProvisionTenant calls Sync when
TENANT_CRD_NAMESPACE is set (empty = no-op, same shape as every other
optional dependency in this codebase). Its "already active" refusal is
now split: ClickHouse re-provisioning is still refused (rotating a live
credential would break every open connection for no benefit), but CR
sync alone is now retryable using the credentials already on file in
rbacstore -- needed for retrying a previously-failed sync, or
backfilling CR sync for a tenant provisioned before this existed.

deploy/operator's reconciler rewritten to match: it never claims
PhaseActive on its own initiative anymore, only once
status.ClickHouseDatabaseName is non-empty (the field -provision-tenant,
and only -provision-tenant, sets). Phase is now a pure function of
{spec.suspended, status.ClickHouseDatabaseName != ""} recomputed every
reconcile, not toggled in place -- fixes a related bug the old code
would have hit once suspension was involved: un-suspending an
already-provisioned tenant needs to return straight to Active, which
isn't derivable from "last observed phase was Suspended" alone. The
reconciler no longer creates or manages any Secret, dropped its
`secrets` RBAC grant entirely, and gained zero new dependencies.

Helm chart: enterprise-api gets its own ServiceAccount/Role/RoleBinding
(get/list/create tenants, get/update/patch tenants/status, get/create/
update secrets -- least-privilege, scoped to the release namespace, not
a ClusterRole) and a TENANT_CRD_NAMESPACE env var, both gated on
tenantOperator.enabled. tenant-operator's ClusterRole loses the
secrets grant it no longer needs.

Verified in this environment: enterprise/internal/tenantcrd's tests run
against k8s.io/client-go's fake dynamic + typed clientsets (real client
library, fake transport, no cluster needed); deploy/operator's rewritten
tenant_controller_test.go runs against controller-runtime's fake
client, including new regression tests for the "must not claim Active
without confirmation" and "un-suspending returns to Active, not
Provisioning" properties; helm template + parsing the rendered YAML
confirms the RBAC split renders exactly as designed under both
tenantOperator.enabled=true/false. Not verified: an actual
-provision-tenant run against a real cluster with the operator watching
(no live cluster in this environment, same disclosed limitation as the
rest of /deploy). Docs updated in lockstep: CLAUDE.md, docs/architecture.md,
deploy/README.md, deploy/helm/sentry/README.md (including a corrected
"Trying the two-tenant example" walkthrough), phase-4-runbook.md (new
§11), enterprise/README.md. Also fixed two unrelated stale claims found
along the way: docs/architecture.md still said docker-compose.yml ran
plain api unconditionally (fixed in an earlier commit, doc not updated
then), and enterprise-api's own main.go doc comment still said Helm/
docker-compose wiring wasn't built yet.

docs/architecture.md

@@ -146,23 +146,29 @@ escape hatch is opaque to any compiler-injected filter.
   query time — and permanently empty until something upstream of
   `chrunner`/`searchclient` becomes tenant-aware on the write side,
   which is undesigned, not merely unbuilt.
-- `deploy/operator`'s `Tenant` CRD still manages only the K8s-side
-  artifact (a credential Secret); it doesn't call
-  `enterprise-api -provision-tenant` or otherwise trigger ClickHouse-side
-  provisioning. The two mechanisms are independent today, not reconciled
-  into one state machine.
+- `deploy/operator`'s `Tenant` CRD and `enterprise-api -provision-tenant`
+  are now unified, deliberately lightweight: `-provision-tenant` stays
+  the sole real actor (ClickHouse + `rbacstore`), and now also syncs its
+  real result into the `Tenant` CRD (`enterprise/internal/tenantcrd`) --
+  a real credential Secret, and status fields the reconciler
+  (`deploy/operator/internal/controller`) derives `Phase`/`Ready` from
+  rather than independently guessing. The reconciler itself gained no
+  new credentials and still never touches ClickHouse/Postgres.
 
-**The deployment-topology gap is closed for the Helm chart**: `deploy/
-helm/sentry/templates/api.yaml`/`enterprise-api.yaml` are mutually
-exclusive on `enterprise.enabled`, rendering to the same Service name
-and port either way, so a Helm-deployed cluster can't accidentally run
-the wrong binary — the same flag that turns on RBAC/audit/SSO now also
-chooses the query binary. `docker-compose.yml` still runs plain `api`
-unconditionally, so this enforcement doesn't yet extend to local/dev.
-With both storage engines' connection/index-layer mechanisms built and
-deployment topology enforced at the Helm layer, the largest remaining
-gaps are ingest's lack of tenant-awareness (undesigned) and unifying the
-`Tenant` CRD with `-provision-tenant` into one provisioning flow.
+**The deployment-topology gap is closed for both Helm and
+docker-compose**: `deploy/helm/sentry/templates/api.yaml`/
+`enterprise-api.yaml` are mutually exclusive on `enterprise.enabled`,
+rendering to the same Service name and port either way, so a
+Helm-deployed cluster can't accidentally run the wrong binary — the same
+flag that turns on RBAC/audit/SSO now also chooses the query binary.
+`docker-compose.yml`'s `api`/`enterprise-api` services are the same
+mutually-exclusive choice via `COMPOSE_PROFILES` (`.env` defaults to
+plain `api`), sharing a host-port/network-alias trick so `alerting`/
+`web` need no conditional config either way. With both storage engines'
+connection/index-layer mechanisms built, deployment topology enforced at
+both the Helm and docker-compose layers, and the two provisioning
+mechanisms unified, the largest remaining gap is ingest's lack of
+tenant-awareness, which is undesigned, not merely unbuilt.
 
 ## Licensing boundary