feat(keycloak): M4.3 — Admin API adapter + claim resolver

internal/keycloak/ — Adapter interface with two implementations:
  HTTPAdapter  pgxpool-style real Admin API client with cached client-
               credentials token (auto-refresh, 401 retry).
  Mock         in-process map for unit tests + dev convenience when
               KEYCLOAK_ADMIN_URL is empty. Used by the eachStore harness.

Adapter contract (adapter.go):
  CreateOrgAndInvite(ctx, InviteInput) (*InviteResult, error)
    Creates a KC organization, an IT_ADMIN user, adds the user as a
    member, triggers VERIFY_EMAIL + UPDATE_PASSWORD execute-actions
    email. Atomic from the caller's PoV; partial failures surface as
    typed errors (ErrOrgConflict, ErrUserConflict, ErrUnauthorized,
    ErrUnavailable).
  SyncClaims(ctx, userID, Claims) error
    Pushes tenant_id / tenant_slug / org_roles / products / plan /
    tenant_status into the user's KC attributes — the same shape the
    realm's protocol mappers project into JWTs.
  Health(ctx) error
    Pings /admin/serverinfo; wired into readyz.

Wiring:
  POST /v1/tenants now accepts admin_email + admin_name. When set, the
  adapter creates the org and invites the user. Response wraps the
  tenant with the new TenantCreated{tenant, invite_url} shape so dev
  testers can use the action-token URL without waiting for the email.
  KC failures DO NOT roll the tenant back — they emit a
  keycloak.provision_failed audit event so the operator can resend.
  Successful invites emit keycloak.invite_sent.

  POST /v1/internal/keycloak/claims resolves a tenant's current claim
  bundle. Lookup chain: body.tenant_id → body.tenant_slug →
  body.user_attrs.tenant_id → body.user_attrs.tenant_slug. The realm's
  protocol mapper calls this at token issuance, or operators on demand.

Config: KEYCLOAK_ADMIN_URL / REALM / CLIENT_ID / CLIENT_SECRET; empty
URL falls back to Mock for dev.

OpenAPI: TenantCreated + Claims schemas added; /v1/internal/keycloak/claims
documented. Contract test extended to cover the new endpoint.

Tests:
  internal/keycloak/mock_test.go    Mock semantics: conflict surfacing,
                                    FailNext hook, SyncClaims persistence.
  internal/server/keycloak_test.go  KC provisioning end-to-end via
                                    eachStore: invite_url returned,
                                    mock records, invite_sent audit;
                                    failure path emits provision_failed
                                    but tenant still lands; claims
                                    endpoint resolves via tenant_id /
                                    tenant_slug / user_attrs / 404 / 400.

The real-KC integration test (against a testcontainers-spun KC 26)
lands in a follow-up — gating it behind KEYCLOAK_INTEGRATION=1 + a
slower nightly CI is cleaner than baking 30s+ of KC boot into every PR.

Refs: M4.3

cmd/server/main.go

@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"gitea.meghsakha.com/platform/tenant-registry/internal/config"
+	"gitea.meghsakha.com/platform/tenant-registry/internal/keycloak"
 	"gitea.meghsakha.com/platform/tenant-registry/internal/server"
 	"gitea.meghsakha.com/platform/tenant-registry/internal/store"
 )
@@ -42,7 +43,23 @@ func main() {
 	}
 	defer s.Close()
 
-	handler := server.NewRouter(&server.Server{Cfg: cfg, Log: logger, Store: s})
+	var kc keycloak.Adapter
+	if cfg.KeycloakAdminURL != "" && cfg.KeycloakClientID != "" {
+		kc = keycloak.NewHTTPAdapter(keycloak.HTTPConfig{
+			BaseURL:      cfg.KeycloakAdminURL,
+			Realm:        cfg.KeycloakRealm,
+			ClientID:     cfg.KeycloakClientID,
+			ClientSecret: cfg.KeycloakClientSecret,
+			Timeout:      cfg.KeycloakTimeout,
+		})
+		slog.Info("keycloak adapter configured",
+			"url", cfg.KeycloakAdminURL, "realm", cfg.KeycloakRealm, "client_id", cfg.KeycloakClientID)
+	} else {
+		slog.Warn("KEYCLOAK_ADMIN_URL not set — using mock adapter (dev only; no real KC writes)")
+		kc = keycloak.NewMock()
+	}
+
+	handler := server.NewRouter(&server.Server{Cfg: cfg, Log: logger, Store: s, Keycloak: kc})
 	srv := &http.Server{
 		Addr:         cfg.Addr,
 		Handler:      handler,