test: update stale tests to match current code (#11963)

Seven test files were asserting against older function signatures and
behaviors. CI has been red on main because of accumulated test debt
from other PRs; this catches the tests up.

- tests/agent/test_subagent_progress.py: _build_child_progress_callback
  now takes (task_index, goal, parent_agent, task_count=1); update all
  call sites and rewrite tests that assumed the old 'batch-only' relay
  semantics (now relays per-tool AND flushes a summary at BATCH_SIZE).
  Renamed test_thinking_not_relayed_to_gateway → test_thinking_relayed_to_gateway
  since thinking IS now relayed as subagent.thinking.
- tests/tools/test_delegate.py: _build_child_agent now requires
  task_count; add task_count=1 to all 8 call sites.
- tests/cli/test_reasoning_command.py: AIAgent gained _stream_callback;
  stub it on the two test agent helpers that use spec=AIAgent / __new__.
- tests/hermes_cli/test_cmd_update.py: cmd_update now runs npm install
  in repo root + ui-tui/ + web/ and 'npm run build' in web/; assert
  all four subprocess calls in the expected order.
- tests/hermes_cli/test_model_validation.py: dissimilar unknown models
  now return accepted=False (previously True with warning); update
  both affected tests.
- tests/tools/test_registry.py: include feishu_doc_tool and
  feishu_drive_tool in the expected builtin tool set.
- tests/gateway/test_voice_command.py: missing-voice-deps message now
  suggests 'pip install PyNaCl' not 'hermes-agent[messaging]'.

411/411 pass locally across these 7 files.

tests/cli/test_reasoning_command.py

@@ -473,6 +473,7 @@ class TestInlineThinkBlockExtraction(unittest.TestCase):
         agent.verbose_logging = False
         agent.reasoning_callback = None
         agent.stream_delta_callback = None  # non-streaming by default
+        agent._stream_callback = None  # non-streaming by default
         return agent
 
     def test_single_think_block_extracted(self):
@@ -619,6 +620,7 @@ class TestReasoningDeltasFiredFlag(unittest.TestCase):
         agent = AIAgent.__new__(AIAgent)
         agent.reasoning_callback = None
         agent.stream_delta_callback = None
+        agent._stream_callback = None
         agent.verbose_logging = False
         return agent