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

internal/keycloak/ — Adapter interface with two implementations:
  HTTPAdapter  cached client-credentials token; CreateOrgAndInvite +
               SyncClaims + Health against the real KC Admin API.
  Mock         in-process map for unit tests + dev convenience when
               KEYCLOAK_ADMIN_URL is empty. Used by the eachStore harness.

POST /v1/tenants now accepts admin_email + admin_name. When set, the
adapter creates a KC organization, invites the user as IT_ADMIN, and
triggers VERIFY_EMAIL + UPDATE_PASSWORD. Response wraps the tenant
with TenantCreated{tenant, invite_url}. KC failures DO NOT roll the
tenant back — they emit a keycloak.provision_failed audit event.
Successful invites emit keycloak.invite_sent.

POST /v1/internal/keycloak/claims resolves a tenant's current claim
bundle (tenant_id, slug, products, plan, status). Lookup chain:
body.tenant_id → body.tenant_slug → user_attrs.tenant_id →
user_attrs.tenant_slug.

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

Tests:
  internal/keycloak/mock_test.go     conflict surfacing, FailNext hook,
                                     SyncClaims persistence.
  internal/keycloak/client_test.go   HTTPAdapter against an in-process
                                     stub KC: health, full create-org-
                                     and-invite, conflict, token-cache,
                                     401 retry, ErrUnavailable.
  internal/server/keycloak_test.go   eachStore integration: provisions
                                     via mock; failure path emits
                                     provision_failed audit; claims
                                     endpoint via every lookup variant
                                     + 404 + 400.

OpenAPI extended with TenantCreated + Claims schemas and the new
claims endpoint. Contract test asserts the new path.

CI: include internal/keycloak/... in the test package list so
HTTPAdapter coverage counts. Total project line coverage: 71.6%.

Refs: M4.3

internal/config/config.go

@@ -3,6 +3,7 @@ package config
 import (
 	"fmt"
 	"os"
+	"time"
 )
 
 type Config struct {
@@ -10,6 +11,15 @@ type Config struct {
 	Addr           string // listen address, e.g. ":8090"
 	KeycloakIssuer string // e.g. http://localhost:8080/realms/breakpilot-dev
 	DatabaseURL    string // postgres DSN (unused in skeleton; in-memory store)
+
+	// Keycloak Admin API — only used if KeycloakAdminURL is set. Empty
+	// values disable the adapter and tenant-registry falls back to the
+	// Mock (dev convenience).
+	KeycloakAdminURL     string
+	KeycloakRealm        string
+	KeycloakClientID     string
+	KeycloakClientSecret string
+	KeycloakTimeout      time.Duration
 }
 
 func Load() (*Config, error) {
@@ -23,6 +33,12 @@ func Load() (*Config, error) {
 		Addr:           getenv("ADDR", ":8090"),
 		KeycloakIssuer: getenv("KEYCLOAK_ISSUER", "http://localhost:8080/realms/breakpilot-dev"),
 		DatabaseURL:    os.Getenv("DATABASE_URL"),
+
+		KeycloakAdminURL:     os.Getenv("KEYCLOAK_ADMIN_URL"),
+		KeycloakRealm:        getenv("KEYCLOAK_REALM", "breakpilot-dev"),
+		KeycloakClientID:     os.Getenv("KEYCLOAK_CLIENT_ID"),
+		KeycloakClientSecret: os.Getenv("KEYCLOAK_CLIENT_SECRET"),
+		KeycloakTimeout:      10 * time.Second,
 	}, nil
 }