test(ai_client): rename send_result to send in 22 remaining test files

Batch rename of 22 test files. 62 references renamed total.

The full test suite is now GREEN again, matching the pre-rename baseline
from Task 1.1. Pure mechanical rename. No behavior change.

Files affected: test_ai_cache_tracking, test_ai_client_cli,
test_ai_client_result, test_api_events, test_context_pruner,
test_deepseek_provider, test_gemini_cli_* (3 files), test_gui2_mcp,
test_headless_* (2 files), test_live_gui_integration_v2,
test_orchestration_logic, test_phase6_engine, test_rag_integration,
test_run_worker_lifecycle_abort, test_spawn_interception_v2,
test_symbol_parsing, test_tier4_interceptor, test_tiered_aggregation,
test_token_usage.

Note: spec estimated 24 files; actual is 22 (test_deprecation_warnings
no longer exists, and 1 fewer file than spec's list).

Refs: conductor/tracks/send_result_to_send_20260616/

tests/test_rag_integration.py

@@ -73,7 +73,7 @@ def test_rag_integration(mock_project):
  # message sent to the provider. We use 'wraps' to let the real logic run 
  # while still having a mock we can inspect. We also mock the internal 
  # _send_gemini which is what actually "sends to the provider".
- with patch('src.ai_client.send_result', wraps=ai_client.send_result) as mock_send:
+ with patch('src.ai_client.send', wraps=ai_client.send) as mock_send:
   with patch('src.ai_client._send_gemini') as mock_provider:
    mock_provider.return_value = Result(data="Mock AI Response")