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

internal/keycloak/mock.go

@@ -0,0 +1,68 @@
+package keycloak
+
+import (
+	"context"
+	"errors"
+	"sync"
+)
+
+// Mock is the test-friendly Adapter. Records every call; predictable IDs.
+// Use in unit tests + as the default adapter when KEYCLOAK_BASE_URL is empty
+// (dev convenience).
+type Mock struct {
+	mu       sync.Mutex
+	Orgs     map[string]string // tenantID → orgID
+	Users    map[string]string // email → userID
+	Claims   map[string]Claims // userID → last synced
+	FailNext error             // set to force the next call to fail
+}
+
+func NewMock() *Mock {
+	return &Mock{
+		Orgs:   map[string]string{},
+		Users:  map[string]string{},
+		Claims: map[string]Claims{},
+	}
+}
+
+func (m *Mock) Health(_ context.Context) error { return nil }
+
+func (m *Mock) CreateOrgAndInvite(_ context.Context, in InviteInput) (*InviteResult, error) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	if m.FailNext != nil {
+		err := m.FailNext
+		m.FailNext = nil
+		return nil, err
+	}
+	if _, taken := m.Orgs[in.TenantID]; taken {
+		return nil, ErrOrgConflict
+	}
+	if _, taken := m.Users[in.AdminEmail]; taken {
+		return nil, ErrUserConflict
+	}
+	orgID := "mock-org-" + in.Slug
+	userID := "mock-user-" + in.AdminEmail
+	m.Orgs[in.TenantID] = orgID
+	m.Users[in.AdminEmail] = userID
+	return &InviteResult{
+		OrganizationID: orgID,
+		UserID:         userID,
+		InviteURL:      "http://mock-keycloak/invite/" + userID,
+	}, nil
+}
+
+func (m *Mock) SyncClaims(_ context.Context, userID string, c Claims) error {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	if m.FailNext != nil {
+		err := m.FailNext
+		m.FailNext = nil
+		return err
+	}
+	if userID == "" {
+		return errors.New("mock: user_id required")
+	}
+	m.Claims[userID] = c
+	return nil
+}