fix(tests): resolve CI test failures — pool auto-seeding, stale assertions, mock isolation

Salvaged from PR #10643 by kshitijk4poor, updated for current main.

Root causes fixed:
1. Telegram xdist mock pollution — new tests/gateway/conftest.py with shared
   mock that runs at collection time (prevents ChatType=None caching)
2. VIRTUAL_ENV env var leak — monkeypatch.delenv in _detect_venv_dir tests
3. Copilot base_url missing — add fallback in _resolve_runtime_from_pool_entry
4. Stale vision model assertion — zai now uses glm-5v-turbo
5. Reasoning item id intentionally stripped — assert 'id' not in (store=False)
6. Context length warning unreachable — pass base_url to AIAgent in test
7. Kimi provider label updated — 'Kimi / Kimi Coding Plan' matches models.py
8. Google Workspace calendar tests — rewritten for current production code,
   properly mock subprocess on api_module, removed stale +agenda assertions
9. Credential pool auto-seeding — mock _select_pool_entry / _resolve_auto /
   _import_codex_cli_tokens to prevent real credentials from leaking into tests

tests/run_agent/test_provider_parity.py

@@ -805,7 +805,10 @@ class TestCodexReasoningPreflight:
         reasoning_items = [i for i in normalized if i.get("type") == "reasoning"]
         assert len(reasoning_items) == 1
         assert reasoning_items[0]["encrypted_content"] == "abc123encrypted"
-        assert reasoning_items[0]["id"] == "r_001"
+        # Note: "id" is intentionally excluded from normalized output —
+        # with store=False the API returns 404 on server-side id resolution.
+        # The id is only used for local deduplication via seen_ids.
+        assert "id" not in reasoning_items[0]
         assert reasoning_items[0]["summary"] == [{"type": "summary_text", "text": "Thinking about it"}]
 
     def test_reasoning_item_without_id(self, monkeypatch):