sea-auth-u2m: refresh test fakes for the merged-kernel binding surface

Rebased onto the updated sea-operation (carrying the #379 review fixes up
the stack). Test-fake refresh:
- execution.test.ts: keep the sessionId getter; executeStatement(sql) only
  (the session-level options migration already on this branch dropped the
  per-statement options).
- _helpers/fakeBinding.ts: cast Connection/Statement through the binding's
  member types instead of bare Function.
- OAuth e2e tests (auth-m2m / auth-u2m): cast the connect literal as
  ConnectionOptions & InternalConnectionOptions for the useSEA opt-in.

Known follow-ups (not test fakes; tracked separately): SeaBackend passes
OAuth options (authMode/oauthClientId) that the merged-kernel binding's
ConnectionOptions does not yet expose — the kernel's OAuth napi surface
must land in main first; and the SeaOperationBackend neutral-type
conformance (status/getResultMetadata) is the sea-results follow-up.

Co-authored-by: Isaac

Author: msrathore-db

tests/e2e/sea/auth-m2m-e2e.test.ts

@@ -16,6 +16,8 @@ import { expect } from 'chai';
 import { DBSQLClient } from '../../../lib';
 import AuthenticationError from '../../../lib/errors/AuthenticationError';
 import { isBlankOrReserved } from '../../../lib/sea/SeaAuth';
+import { ConnectionOptions } from '../../../lib/contracts/IDBSQLClient';
+import { InternalConnectionOptions } from '../../../lib/contracts/InternalConnectionOptions';
 
 /**
  * sea-auth M1 OAuth M2M end-to-end:
@@ -76,7 +78,7 @@ describe('sea-auth e2e — OAuth M2M through DBSQLClient ↔ SeaBackend ↔ napi
       oauthClientId: oauthClientId as string,
       oauthClientSecret: oauthClientSecret as string,
       useSEA: true,
-    });
+    } as ConnectionOptions & InternalConnectionOptions);
     expect(connected).to.equal(client);
 
     const session = await client.openSession();
@@ -103,7 +105,7 @@ describe('sea-auth e2e — OAuth M2M through DBSQLClient ↔ SeaBackend ↔ napi
       oauthClientId: oauthClientId as string,
       oauthClientSecret: 'definitely-not-the-real-secret-deadbeef',
       useSEA: true,
-    });
+    } as ConnectionOptions & InternalConnectionOptions);
 
     let caught: unknown;
     try {

tests/e2e/sea/auth-u2m-e2e.test.ts

@@ -14,6 +14,8 @@
 
 import { expect } from 'chai';
 import { DBSQLClient } from '../../../lib';
+import { ConnectionOptions } from '../../../lib/contracts/IDBSQLClient';
+import { InternalConnectionOptions } from '../../../lib/contracts/InternalConnectionOptions';
 
 /**
  * sea-auth M1 OAuth U2M end-to-end — **SKIPPED pending browser harness**.
@@ -58,7 +60,7 @@ describe('sea-auth e2e — OAuth U2M through DBSQLClient ↔ SeaBackend ↔ napi
       path,
       authType: 'databricks-oauth',
       useSEA: true,
-    });
+    } as ConnectionOptions & InternalConnectionOptions);
     expect(connected).to.equal(client);
 
     const session = await client.openSession();

tests/unit/sea/_helpers/fakeBinding.ts

@@ -52,8 +52,11 @@ export function makeFakeBinding(): FakeBinding {
       calls.push({ method: 'openSession', args: [opts] });
       return fakeConnection as unknown as SeaNativeConnection;
     },
-    Connection: function FakeConnection() {} as unknown as Function,
-    Statement: function FakeStatement() {} as unknown as Function,
+    // Index the binding type for the napi class constructor types; the
+    // loader exports Connection/Statement as type aliases, so `typeof
+    // Connection` is illegal and bare `Function` has no construct signature.
+    Connection: function FakeConnection() {} as unknown as SeaNativeBinding['Connection'],
+    Statement: function FakeStatement() {} as unknown as SeaNativeBinding['Statement'],
   };
 
   return { binding, calls };