fix: migrate legacy admin role to granular roles at startup

- Add migrateAdminRole() that runs on mcpd boot
- Converts { role: 'admin', resource: X } → edit + run bindings
- Adds operation bindings for wildcard admin (impersonate, logs, etc.)
- Add tests verifying unknown/legacy roles are denied by canAccess

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/mcpd/tests/rbac.test.ts

@@ -680,4 +680,52 @@ describe('RbacService', () => {
       expect(perms).toEqual([]);
     });
   });
+
+  describe('unknown/legacy roles are denied', () => {
+    let service: RbacService;
+
+    beforeEach(() => {
+      const repo = mockRepo([
+        makeDef({
+          roleBindings: [{ role: 'admin', resource: '*' }],
+        }),
+      ]);
+      const prisma = mockPrisma({
+        user: { findUnique: vi.fn(async () => ({ email: 'alice@example.com' })) },
+        groupMember: { findMany: vi.fn(async () => []) },
+      });
+      service = new RbacService(repo, prisma);
+    });
+
+    it('denies view when only legacy admin role exists', async () => {
+      expect(await service.canAccess('user-1', 'view', 'servers')).toBe(false);
+    });
+
+    it('denies create when only legacy admin role exists', async () => {
+      expect(await service.canAccess('user-1', 'create', 'servers')).toBe(false);
+    });
+
+    it('denies edit when only legacy admin role exists', async () => {
+      expect(await service.canAccess('user-1', 'edit', 'servers')).toBe(false);
+    });
+
+    it('denies delete when only legacy admin role exists', async () => {
+      expect(await service.canAccess('user-1', 'delete', 'servers')).toBe(false);
+    });
+
+    it('denies any made-up role', async () => {
+      const repo = mockRepo([
+        makeDef({
+          roleBindings: [{ role: 'superuser', resource: 'servers' }],
+        }),
+      ]);
+      const prisma = mockPrisma({
+        user: { findUnique: vi.fn(async () => ({ email: 'alice@example.com' })) },
+        groupMember: { findMany: vi.fn(async () => []) },
+      });
+      const svc = new RbacService(repo, prisma);
+      expect(await svc.canAccess('user-1', 'view', 'servers')).toBe(false);
+      expect(await svc.canAccess('user-1', 'edit', 'servers')).toBe(false);
+    });
+  });
 });