fix(codex-bridge): flatten top-level oneOf/anyOf/allOf in tool schemas for external models

Since bridge 7 external models get Codex's classic tools. One desktop tool has a top-level union schema,
which Claude rejects ("input_schema does not support oneOf, allOf, or anyOf at the top level"), so every
Opus request from the desktop app failed with a bare "upstream 400". The earlier context-size diagnosis
was wrong: the request still failed after compaction (239 KB).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/desktop/assets/codex-bridge/test_access_programs.py

@@ -31,7 +31,7 @@ class AccessPrograms(unittest.TestCase):
             "fix_tool_ids": lambda req: 0,
             "drop_foreign_items": lambda req: 0,
             "SseRewriter": Mock(),
-            "log": lambda message: None, "pencere": __import__("pencere"), "IDE_BILGI": {}, "yarim": __import__("yarim"), "is_hatti": __import__("is_hatti"), "GORULEN_ISTEMCI": set(), "nokta_mesaji_mi": lambda req: False, "EXTRA_MODELS": [],
+            "log": lambda message: None, "pencere": __import__("pencere"), "IDE_BILGI": {}, "yarim": __import__("yarim"), "is_hatti": __import__("is_hatti"), "GORULEN_ISTEMCI": set(), "arac_semalarini_duzelt": lambda req: 0, "nokta_mesaji_mi": lambda req: False, "EXTRA_MODELS": [],
             "DEBUG": False, "UA": "test", "RETRIES": 1, "UPSTREAM_IDLE_TIMEOUT": 3900,
         }
         exec(compile(ast.Module(body=[flatten, claude_sonu, responses], type_ignores=[]), "bridge.py", "exec"), self.env)