fix(auth/rbac): scope-aware ActorRole revoke (A-4)

HIGH-10's UNIQUE (actor, role, scope_type, scope_id, tenant) uniqueness
extension lets an operator grant the same role to the same actor at
multiple scopes (e.g. r-operator on profile=p-acme AND profile=p-globex).
But ActorRoleRepository.Revoke's WHERE clause omitted (scope_type,
scope_id) — a single call deleted every variant. Selective revoke was
unrepresentable; operators had to drop all and re-grant N-1, opening
a race window where the actor's access was briefly different.

Closure across all layers (handler → service → repo → MCP → GUI client),
preserving the legacy "revoke all variants" contract for unmodified
callers:

  internal/repository/auth.go
    - New ActorRoleRevokeOptions struct. Zero value = legacy semantic;
      non-empty ScopeType narrows to one variant.
    - New ErrActorRoleNotFound sentinel for scoped no-match (HTTP 404).

  internal/repository/postgres/auth.go
    - Revoke signature extended with opts. Empty opts.ScopeType uses
      the legacy SQL (no scope WHERE), zero-row delete = no error.
    - Non-empty narrows with `scope_type = $5 AND scope_id IS NOT
      DISTINCT FROM $6` — the IS-NOT-DISTINCT-FROM is load-bearing,
      vanilla `=` would silently miss the (global, NULL) case because
      NULL ≠ NULL in standard SQL.
    - Selective revoke with zero matching rows returns
      ErrActorRoleNotFound; operators get feedback on typos.

  internal/service/auth/actor_role_service.go
    - Revoke takes opts. Audit row's details map records the scope so
      SIEMs can distinguish wide-vs-selective revokes:
      `scope: "all_variants"` for the legacy path, or
      `scope_type` + `scope_id` for selective. Privilege check
      (auth.role.assign) and reserved-actor guard unchanged.

  internal/api/handler/auth.go
    - RevokeRoleFromKey parses optional `?scope_type=` / `?scope_id=`
      query params via new parseRevokeScope helper.
    - Validation mirrors AssignRoleToKey: scope_id forbidden with
      scope_type=global, required with profile/issuer, invalid
      scope_type → 400. scope_id without scope_type also → 400.
    - writeAuthError maps ErrActorRoleNotFound to 404.

  internal/mcp/tools_auth.go + types.go
    - AuthRevokeKeyRoleInput gains optional ScopeType + ScopeID with
      jsonschema descriptions explaining the dual-mode contract.
    - Tool call site appends URL-encoded query params when ScopeType
      is set; legacy callers (no scope_type) emit the bare DELETE
      path unchanged.

  web/src/api/client.ts
    - authRevokeKeyRole signature: optional 3rd argument
      `{ scope_type?, scope_id? }`. Pre-A-4 call sites (no opts arg)
      keep firing the bare DELETE — fully backward compatible. The
      GUI KeysPage's per-row revoke button (still one row per role,
      pre-Fix-12) continues to use the legacy shape; future GUI work
      can pass scope params for per-variant rows.

  docs/operator/rbac.md
    - New "Revoke: legacy 'all variants' vs scope-selective" subsection
      under "From the HTTP API" with curl examples for both modes plus
      the audit-row payload shape that lets SOC/SIEM tell them apart.

Regression coverage:

  Repository (testcontainers, skipped under -short — 6 tests in
  internal/repository/postgres/auth_revoke_scope_test.go):
    TestRevokeActorRole_NoOpts_RemovesAllVariants
    TestRevokeActorRole_WithScope_RemovesOnlyMatching
    TestRevokeActorRole_WithGlobalScope_RemovesOnlyGlobal — pins the
      IS-NOT-DISTINCT-FROM branch (global, NULL)
    TestRevokeActorRole_NoMatch_ReturnsNotFound — pins the new sentinel
    TestRevokeActorRole_NoOpts_NoMatch_IsNoOp — pins the legacy
      idempotence contract
    TestRevokeActorRole_IssuerScope_RemovesOnlyMatching — pin the
      issuer-scope half (profile + issuer are symmetric scope types)

  Handler (7 new tests in auth_test.go):
    TestAuthHandler_RevokeRoleFromKey — extended to assert no scope
      filter is forwarded when query string is empty (legacy behaviour)
    TestAuthHandler_RevokeRoleFromKey_A4_ScopedProfile
    TestAuthHandler_RevokeRoleFromKey_A4_ScopedGlobal
    TestAuthHandler_RevokeRoleFromKey_A4_RejectsScopeIDWithGlobal
    TestAuthHandler_RevokeRoleFromKey_A4_RejectsMissingScopeID
    TestAuthHandler_RevokeRoleFromKey_A4_RejectsScopeIDWithoutScopeType
    TestAuthHandler_RevokeRoleFromKey_A4_RejectsInvalidScopeType
    TestAuthHandler_RevokeRoleFromKey_A4_ScopedNotFoundReturns404

  MCP (2 new table rows in tools_per_tool_test.go):
    Scoped revoke with scope_type=profile + scope_id=p-acme →
      `?scope_type=profile&scope_id=p-acme`
    Scoped revoke with scope_type=global (no scope_id) →
      `?scope_type=global`

Service-layer test plumbing (service_test.go) updated for new opts
arg: 4 existing call sites pass repository.ActorRoleRevokeOptions{}
to keep their pre-A-4 semantics; the fakeActorRoleRepo.Revoke
implementation now mirrors the postgres scope-aware behaviour
(legacy zero-value vs scoped narrowing + ErrActorRoleNotFound on
no-match).

Verify gate green: gofmt clean, go vet clean, go test -short across
repository/postgres, service/auth, api/handler, and mcp. The
pre-existing KeysPage.test.tsx failure observed on the baseline
commit (reproduced via `git stash` earlier in Fix 03) is unrelated;
my client.ts change adds an optional third argument and is fully
backward-compatible.

Spec at cowork/auth-bundles-fixes-2026-05-11/04-high-actor-role-revoke-scope.md.
Audit doc updated: new row A-4 (2026-05-11) CLOSED appended to the
status table at the bottom of cowork/auth-bundles-audit-2026-05-10.md.
Operator-visible advisory in CHANGELOG.md v2.1.0 release notes under
Security (non-BREAKING — legacy callers are unchanged).

Depends on Fix 01 (the scope-aware EffectivePermissions read path on
branch fix/audit-2026-05-11/crit-actor-role-scope-reads). This fix
makes the inverse op selectively reversible; without Fix 01 the read
side would mis-evaluate scoped grants anyway, making selective revoke
moot at runtime.

internal/api/handler/auth_test.go

@@ -122,6 +122,13 @@ type fakeAuthActorSvc struct {
 	revokeErr error
 	roles     []*authdomain.ActorRole
 	effective []repository.EffectivePermission
+	// Audit 2026-05-11 A-4 — capture Revoke opts so tests can assert
+	// that the handler forwards scope_type / scope_id correctly.
+	revokeOpts repository.ActorRoleRevokeOptions
+	revokeCall struct {
+		actorID, roleID string
+		called          bool
+	}
 }
 
 func newFakeAuthActorSvc() *fakeAuthActorSvc {
@@ -134,7 +141,11 @@ func (f *fakeAuthActorSvc) Grant(_ context.Context, _ *authsvc.Caller, ar *authd
 	f.roles = append(f.roles, ar)
 	return nil
 }
-func (f *fakeAuthActorSvc) Revoke(_ context.Context, _ *authsvc.Caller, _ string, _ domain.ActorType, _ string) error {
+func (f *fakeAuthActorSvc) Revoke(_ context.Context, _ *authsvc.Caller, actorID string, _ domain.ActorType, roleID string, opts repository.ActorRoleRevokeOptions) error {
+	f.revokeCall.called = true
+	f.revokeCall.actorID = actorID
+	f.revokeCall.roleID = roleID
+	f.revokeOpts = opts
 	return f.revokeErr
 }
 func (f *fakeAuthActorSvc) ListForActor(_ context.Context, _ *authsvc.Caller, _ string, _ domain.ActorType) ([]*authdomain.ActorRole, error) {
@@ -440,7 +451,7 @@ func TestAuthHandler_AssignRoleSelfRoleAssignReturns403(t *testing.T) {
 }
 
 func TestAuthHandler_RevokeRoleFromKey(t *testing.T) {
-	h, _, _, _ := newAuthHandlerWithFakes()
+	h, _, _, actorSvc := newAuthHandlerWithFakes()
 	req := withAuthCtx(httptest.NewRequest(http.MethodDelete, "/api/v1/auth/keys/alice/roles/r-viewer", nil), "admin", auth.ActorTypeAPIKey)
 	req.SetPathValue("id", "alice")
 	req.SetPathValue("role_id", "r-viewer")
@@ -449,6 +460,136 @@ func TestAuthHandler_RevokeRoleFromKey(t *testing.T) {
 	if rec.Code != http.StatusNoContent {
 		t.Errorf("revoke should be 204; got %d", rec.Code)
 	}
+	// Audit 2026-05-11 A-4 — no scope params → legacy "revoke all
+	// variants" semantic propagates as the zero-value
+	// ActorRoleRevokeOptions to the service layer.
+	if actorSvc.revokeOpts.ScopeType != "" {
+		t.Errorf("legacy DELETE forwarded a scope filter: ScopeType=%q", actorSvc.revokeOpts.ScopeType)
+	}
+	if actorSvc.revokeOpts.ScopeID != nil {
+		t.Errorf("legacy DELETE forwarded a scope_id: %v", actorSvc.revokeOpts.ScopeID)
+	}
+}
+
+// =============================================================================
+// Audit 2026-05-11 A-4 — scope-aware revoke handler tests.
+// =============================================================================
+
+func TestAuthHandler_RevokeRoleFromKey_A4_ScopedProfile(t *testing.T) {
+	h, _, _, actorSvc := newAuthHandlerWithFakes()
+	req := withAuthCtx(httptest.NewRequest(http.MethodDelete,
+		"/api/v1/auth/keys/alice/roles/r-operator?scope_type=profile&scope_id=p-acme", nil),
+		"admin", auth.ActorTypeAPIKey)
+	req.SetPathValue("id", "alice")
+	req.SetPathValue("role_id", "r-operator")
+	rec := httptest.NewRecorder()
+	h.RevokeRoleFromKey(rec, req)
+	if rec.Code != http.StatusNoContent {
+		t.Fatalf("scoped revoke should be 204; got %d body=%s", rec.Code, rec.Body.String())
+	}
+	if actorSvc.revokeOpts.ScopeType != authdomain.ScopeTypeProfile {
+		t.Errorf("ScopeType = %q; want profile", actorSvc.revokeOpts.ScopeType)
+	}
+	if actorSvc.revokeOpts.ScopeID == nil || *actorSvc.revokeOpts.ScopeID != "p-acme" {
+		t.Errorf("ScopeID = %v; want p-acme", actorSvc.revokeOpts.ScopeID)
+	}
+}
+
+func TestAuthHandler_RevokeRoleFromKey_A4_ScopedGlobal(t *testing.T) {
+	h, _, _, actorSvc := newAuthHandlerWithFakes()
+	req := withAuthCtx(httptest.NewRequest(http.MethodDelete,
+		"/api/v1/auth/keys/alice/roles/r-operator?scope_type=global", nil),
+		"admin", auth.ActorTypeAPIKey)
+	req.SetPathValue("id", "alice")
+	req.SetPathValue("role_id", "r-operator")
+	rec := httptest.NewRecorder()
+	h.RevokeRoleFromKey(rec, req)
+	if rec.Code != http.StatusNoContent {
+		t.Fatalf("scoped revoke (global) should be 204; got %d body=%s", rec.Code, rec.Body.String())
+	}
+	if actorSvc.revokeOpts.ScopeType != authdomain.ScopeTypeGlobal {
+		t.Errorf("ScopeType = %q; want global", actorSvc.revokeOpts.ScopeType)
+	}
+	if actorSvc.revokeOpts.ScopeID != nil {
+		t.Errorf("ScopeID must be nil for scope_type=global; got %v", actorSvc.revokeOpts.ScopeID)
+	}
+}
+
+func TestAuthHandler_RevokeRoleFromKey_A4_RejectsScopeIDWithGlobal(t *testing.T) {
+	h, _, _, actorSvc := newAuthHandlerWithFakes()
+	req := withAuthCtx(httptest.NewRequest(http.MethodDelete,
+		"/api/v1/auth/keys/alice/roles/r-operator?scope_type=global&scope_id=p-acme", nil),
+		"admin", auth.ActorTypeAPIKey)
+	req.SetPathValue("id", "alice")
+	req.SetPathValue("role_id", "r-operator")
+	rec := httptest.NewRecorder()
+	h.RevokeRoleFromKey(rec, req)
+	if rec.Code != http.StatusBadRequest {
+		t.Errorf("global+scope_id should be 400; got %d body=%s", rec.Code, rec.Body.String())
+	}
+	if actorSvc.revokeCall.called {
+		t.Error("service should NOT have been called on validation error")
+	}
+}
+
+func TestAuthHandler_RevokeRoleFromKey_A4_RejectsMissingScopeID(t *testing.T) {
+	h, _, _, actorSvc := newAuthHandlerWithFakes()
+	req := withAuthCtx(httptest.NewRequest(http.MethodDelete,
+		"/api/v1/auth/keys/alice/roles/r-operator?scope_type=profile", nil),
+		"admin", auth.ActorTypeAPIKey)
+	req.SetPathValue("id", "alice")
+	req.SetPathValue("role_id", "r-operator")
+	rec := httptest.NewRecorder()
+	h.RevokeRoleFromKey(rec, req)
+	if rec.Code != http.StatusBadRequest {
+		t.Errorf("profile-without-scope_id should be 400; got %d body=%s", rec.Code, rec.Body.String())
+	}
+	if actorSvc.revokeCall.called {
+		t.Error("service should NOT have been called on validation error")
+	}
+}
+
+func TestAuthHandler_RevokeRoleFromKey_A4_RejectsScopeIDWithoutScopeType(t *testing.T) {
+	h, _, _, _ := newAuthHandlerWithFakes()
+	req := withAuthCtx(httptest.NewRequest(http.MethodDelete,
+		"/api/v1/auth/keys/alice/roles/r-operator?scope_id=p-acme", nil),
+		"admin", auth.ActorTypeAPIKey)
+	req.SetPathValue("id", "alice")
+	req.SetPathValue("role_id", "r-operator")
+	rec := httptest.NewRecorder()
+	h.RevokeRoleFromKey(rec, req)
+	if rec.Code != http.StatusBadRequest {
+		t.Errorf("scope_id-without-scope_type should be 400; got %d body=%s", rec.Code, rec.Body.String())
+	}
+}
+
+func TestAuthHandler_RevokeRoleFromKey_A4_RejectsInvalidScopeType(t *testing.T) {
+	h, _, _, _ := newAuthHandlerWithFakes()
+	req := withAuthCtx(httptest.NewRequest(http.MethodDelete,
+		"/api/v1/auth/keys/alice/roles/r-operator?scope_type=bogus", nil),
+		"admin", auth.ActorTypeAPIKey)
+	req.SetPathValue("id", "alice")
+	req.SetPathValue("role_id", "r-operator")
+	rec := httptest.NewRecorder()
+	h.RevokeRoleFromKey(rec, req)
+	if rec.Code != http.StatusBadRequest {
+		t.Errorf("bogus scope_type should be 400; got %d", rec.Code)
+	}
+}
+
+func TestAuthHandler_RevokeRoleFromKey_A4_ScopedNotFoundReturns404(t *testing.T) {
+	h, _, _, actorSvc := newAuthHandlerWithFakes()
+	actorSvc.revokeErr = repository.ErrActorRoleNotFound
+	req := withAuthCtx(httptest.NewRequest(http.MethodDelete,
+		"/api/v1/auth/keys/alice/roles/r-operator?scope_type=profile&scope_id=p-globex", nil),
+		"admin", auth.ActorTypeAPIKey)
+	req.SetPathValue("id", "alice")
+	req.SetPathValue("role_id", "r-operator")
+	rec := httptest.NewRecorder()
+	h.RevokeRoleFromKey(rec, req)
+	if rec.Code != http.StatusNotFound {
+		t.Errorf("ErrActorRoleNotFound should be 404; got %d", rec.Code)
+	}
 }
 
 func TestAuthHandler_RevokeReservedActorReturns409(t *testing.T) {