feat(oidc): Enabled toggle on OIDCProvider (MED-9)

Audit 2026-05-10 Fix 13 Phase B — close MED-9. MED-4/5/6/7 deferred to v3.

MED-9: ship the OIDCProvider.Enabled boolean. Pre-fix, the only way
to take a provider offline during an incident was DELETE, which
breaks active user_oidc_provider FK references and orphans any
session that minted under the provider. Post-fix:

  - Migration 000042 adds enabled BOOLEAN NOT NULL DEFAULT TRUE.
    Default-true means existing pre-migration rows are all enabled
    post-deploy; no breaking-change window.
  - internal/auth/oidc/domain/types.go::OIDCProvider.Enabled ships
    the domain field with JSON tag 'enabled'.
  - Repository read/write paths (List, Get, GetByName, Create, Update)
    all carry the column.
  - internal/auth/oidc/service.go::HandleAuthRequest rejects with
    the new ErrProviderDisabled sentinel when cfgRow.Enabled=false.
  - cmd/server/main.go::oidcProvidersListAdapter.List filters
    disabled providers before constructing OIDCProviderInfo so the
    LoginPage's 'Sign in with X' buttons never render for offline
    IdPs.
  - Defense-in-depth: the ErrProviderDisabled service-layer check
    is the guard for direct API / MCP / CLI callers that bypass the
    GUI.

Regression test: internal/auth/oidc/provider_enabled_test.go warms
the entry cache via a successful HandleAuthRequest, flips
cfgRow.Enabled=false on the cached entry, then asserts the next call
returns ErrProviderDisabled (errors.Is). Test fixtures (newValidProvider,
makeProvider) updated to set Enabled: true so existing tests stay
green.

Operators can toggle Enabled today via the existing PUT
/api/v1/auth/oidc/providers/{id} body field. A dedicated GUI
toggle on OIDCProviderDetailPage and a single-purpose PUT-just-enabled
endpoint are deferred to the v3 GUI-polish bundle — the load-bearing
wire is in place now.

MED-4 (GUI advanced fields on edit), MED-5 (POST .../test endpoint
+ button), MED-6 (JWKS auto-refresh on cache-miss), MED-7 (JWKS
health endpoint + GUI panel): DEFERRED to v3 with explicit
annotations in the audit doc. Workarounds: MED-4 fields are
PUT-editable via curl/MCP; MED-5 → call refresh post-create;
MED-6 → call refresh manually on key rotation.

Refs: cowork/auth-bundles-audit-2026-05-10.md MED-4, MED-5, MED-6,
      MED-7, MED-9
Spec: cowork/auth-bundles-fixes-2026-05-10/13-med-bundle.md Phase B

internal/repository/postgres/oidc.go

@@ -27,11 +27,14 @@ func NewOIDCProviderRepository(db *sql.DB) *OIDCProviderRepository {
 	return &OIDCProviderRepository{db: db}
 }
 
+// Audit 2026-05-10 MED-9: `enabled` column added to the SELECT/INSERT/
+// UPDATE column list. Migration 000042 added the column with default
+// TRUE; existing rows are all enabled post-migration.
 const oidcProviderColumns = `id, tenant_id, name, issuer_url, client_id,
 		client_secret_encrypted, redirect_uri, groups_claim_path,
 		groups_claim_format, fetch_userinfo, scopes,
 		allowed_email_domains, iat_window_seconds,
-		jwks_cache_ttl_seconds, created_at, updated_at`
+		jwks_cache_ttl_seconds, enabled, created_at, updated_at`
 
 func scanOIDCProvider(row interface{ Scan(...interface{}) error }) (*oidcdomain.OIDCProvider, error) {
 	var p oidcdomain.OIDCProvider
@@ -41,7 +44,7 @@ func scanOIDCProvider(row interface{ Scan(...interface{}) error }) (*oidcdomain.
 		&p.ClientSecretEncrypted, &p.RedirectURI, &p.GroupsClaimPath,
 		&p.GroupsClaimFormat, &p.FetchUserinfo, &scopes,
 		&domains, &p.IATWindowSeconds,
-		&p.JWKSCacheTTLSeconds, &p.CreatedAt, &p.UpdatedAt,
+		&p.JWKSCacheTTLSeconds, &p.Enabled, &p.CreatedAt, &p.UpdatedAt,
 	); err != nil {
 		return nil, err
 	}
@@ -104,19 +107,24 @@ func (r *OIDCProviderRepository) GetByName(ctx context.Context, tenantID, name s
 // Translates SQLSTATE 23505 (unique_violation) to
 // ErrOIDCProviderDuplicateName.
 func (r *OIDCProviderRepository) Create(ctx context.Context, p *oidcdomain.OIDCProvider) error {
+	// MED-9: persist `enabled` on Create. New providers default to
+	// enabled=true; the schema column also has DEFAULT TRUE, so an
+	// older client sending the pre-MED-9 row shape without the column
+	// would still get enabled=true. We pass the field explicitly to
+	// honor a `Enabled=false` create.
 	_, err := r.db.ExecContext(ctx, `
 		INSERT INTO oidc_providers (
 			id, tenant_id, name, issuer_url, client_id,
 			client_secret_encrypted, redirect_uri, groups_claim_path,
 			groups_claim_format, fetch_userinfo, scopes,
 			allowed_email_domains, iat_window_seconds,
-			jwks_cache_ttl_seconds
-		) VALUES ($1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11,$12,$13,$14)`,
+			jwks_cache_ttl_seconds, enabled
+		) VALUES ($1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11,$12,$13,$14,$15)`,
 		p.ID, p.TenantID, p.Name, p.IssuerURL, p.ClientID,
 		p.ClientSecretEncrypted, p.RedirectURI, p.GroupsClaimPath,
 		p.GroupsClaimFormat, p.FetchUserinfo, pq.StringArray(p.Scopes),
 		pq.StringArray(p.AllowedEmailDomains), p.IATWindowSeconds,
-		p.JWKSCacheTTLSeconds,
+		p.JWKSCacheTTLSeconds, p.Enabled,
 	)
 	if err != nil {
 		var pqErr *pq.Error
@@ -131,6 +139,8 @@ func (r *OIDCProviderRepository) Create(ctx context.Context, p *oidcdomain.OIDCP
 // Update writes the mutable fields back. Immutable: id, tenant_id,
 // created_at. updated_at = NOW().
 func (r *OIDCProviderRepository) Update(ctx context.Context, p *oidcdomain.OIDCProvider) error {
+	// MED-9: persist `enabled` on Update so the toggle endpoint and
+	// the regular update path share the same write surface.
 	res, err := r.db.ExecContext(ctx, `
 		UPDATE oidc_providers SET
 			name = $2,
@@ -145,13 +155,14 @@ func (r *OIDCProviderRepository) Update(ctx context.Context, p *oidcdomain.OIDCP
 			allowed_email_domains = $11,
 			iat_window_seconds = $12,
 			jwks_cache_ttl_seconds = $13,
+			enabled = $14,
 			updated_at = NOW()
 		WHERE id = $1`,
 		p.ID, p.Name, p.IssuerURL, p.ClientID,
 		p.ClientSecretEncrypted, p.RedirectURI, p.GroupsClaimPath,
 		p.GroupsClaimFormat, p.FetchUserinfo, pq.StringArray(p.Scopes),
 		pq.StringArray(p.AllowedEmailDomains), p.IATWindowSeconds,
-		p.JWKSCacheTTLSeconds,
+		p.JWKSCacheTTLSeconds, p.Enabled,
 	)
 	if err != nil {
 		var pqErr *pq.Error

internal/repository/postgres/oidc_test.go

@@ -36,6 +36,7 @@ func newValidProvider(suffix string) *oidcdomain.OIDCProvider {
 		AllowedEmailDomains:   []string{},
 		IATWindowSeconds:      300,
 		JWKSCacheTTLSeconds:   3600,
+		Enabled:               true, // MED-9: default-on for test fixtures
 	}
 }