Make hosted OAuth and MCP auth generic (#1375)

* Make hosted OAuth and MCP auth generic

* Address PR feedback and lint issues

* Suppress built-in Google secret in hosted proxy flows

* Align hosted OAuth secret suppression with proxy config

* Harden hosted OAuth callback helpers

* Tighten hosted OAuth URL rewriting

tests/e2e/mock_llm.py

@@ -267,14 +267,24 @@ async def _stream_tool_call(request: web.Request, cid: str, tc: dict) -> web.Str
 async def oauth_exchange(request: web.Request) -> web.Response:
     """Mock OAuth token exchange proxy for E2E tests.
 
-    Accepts form params (code, redirect_uri, code_verifier) and returns
-    a fake token response. Called by ironclaw's exchange_via_proxy() when
-    IRONCLAW_OAUTH_EXCHANGE_URL is set.
+    Accepts the generic hosted OAuth proxy contract used by IronClaw and
+    returns a fake token response. MCP callback tests assert that provider-
+    specific token params such as RFC 8707 `resource` are forwarded here.
     """
     data = await request.post()
     code = data.get("code", "")
+    access_token_field = data.get("access_token_field", "access_token")
+
+    if code == "mock_mcp_code":
+        if not data.get("token_url", "").endswith("/oauth/token"):
+            return web.json_response({"error": "missing_token_url"}, status=400)
+        if not data.get("client_id"):
+            return web.json_response({"error": "missing_client_id"}, status=400)
+        if not data.get("resource"):
+            return web.json_response({"error": "missing_resource"}, status=400)
+
     return web.json_response({
-        "access_token": f"mock-token-{code}",
+        access_token_field: f"mock-token-{code}",
         "refresh_token": "mock-refresh-token",
         "expires_in": 3600,
     })

tests/e2e/scenarios/test_mcp_auth_flow.py

@@ -99,6 +99,10 @@ async def test_mcp_activate_triggers_auth(ironclaw_server):
     assert auth_url is not None or awaiting_token, (
         f"Activate should require auth, got: {data}"
     )
+    if auth_url is not None:
+        assert _extract_state(auth_url).startswith("ic2."), (
+            f"Hosted MCP OAuth should emit versioned state, got: {auth_url}"
+        )
 
 
 # ── Section C: OAuth Round-Trip ──────────────────────────────────────────