fix: URL-based auth for third-party Anthropic endpoints + CI test fixes (#4148)

* fix(tests): mock sys.stdin.isatty for cmd_model TTY guard

* fix(tests): update camofox snapshot format + trajectory compressor mock path

- test_browser_camofox: mock response now uses snapshot format (accessibility tree)
- test_trajectory_compressor: mock _get_async_client instead of setting async_client directly

* fix: URL-based auth detection for third-party Anthropic endpoints + test fixes

Reverts the key-prefix approach from #4093 which broke JWT and managed
key OAuth detection. Instead, detects third-party endpoints by URL:
if base_url is set and isn't anthropic.com, it's a proxy (Azure AI
Foundry, AWS Bedrock, etc.) that uses x-api-key regardless of key format.

Auth decision chain is now:
1. _requires_bearer_auth(url) → MiniMax → Bearer
2. _is_third_party_anthropic_endpoint(url) → Azure/Bedrock → x-api-key
3. _is_oauth_token(key) → OAuth on direct Anthropic → Bearer
4. else → x-api-key

Also includes test fixes from PR #4051 by @erosika:
- Mock sys.stdin.isatty for cmd_model TTY guard
- Update camofox snapshot format mock
- Fix trajectory compressor async client mock path

---------

Co-authored-by: Erosika <eri@plasticlabs.ai>

tests/tools/test_browser_camofox.py

@@ -235,8 +235,13 @@ class TestCamofoxGetImages:
         mock_post.return_value = _mock_response(json_data={"tabId": "tab10", "url": "https://x.com"})
         camofox_navigate("https://x.com", task_id="t10")
 
+        # camofox_get_images parses images from the accessibility tree snapshot
+        snapshot_text = (
+            '- img "Logo"\n'
+            '  /url: https://x.com/img.png\n'
+        )
         mock_get.return_value = _mock_response(json_data={
-            "images": [{"src": "https://x.com/img.png", "alt": "Logo"}],
+            "snapshot": snapshot_text,
         })
         result = json.loads(camofox_get_images(task_id="t10"))
         assert result["success"] is True