TIER-2 READ conductor/code_styleguides/error_handling.md end-to-end before Phase 10: refactor(gui_2): migrate L1152 _gui_func entry log to Result[T] (Phase 10 site 6)

Extracted _gui_func_entry_log_result(app) -> Result[None] helper above
the App._gui_func method.
ANTI-SLIMING: full Result[T] propagation (NO except+pass-after-log).
The helper returns Result(data=None) on success or Result(data=None,
errors=[ErrorInfo]) on exception (logging NOT a drain per the user's
principle 2026-06-17).

The legacy _gui_func method preserves its signature, calls the helper,
drains errors to self._last_request_errors, and proceeds with the
rest of the render loop.

Tests: 2 new tests verify both paths (success and OSError).

Audit: L1152 reclassified from INTERNAL_SILENT_SWALLOW (8 sites remaining,
was 9). New helper L1152 is INTERNAL_COMPLIANT.

tests/test_gui_2_result.py

@@ -1947,4 +1947,47 @@ def test_phase_10_l1052_shutdown_save_ini_result_failure():
  assert "disk full" in err.message
 
 
+def test_phase_10_l1152_gui_func_entry_log_result_success():
+ """
+ L1152 _gui_func_entry_log_result returns Result(data=None) on success.
+
+ The helper extracts the startup-timing sys.stderr.write from
+ App._gui_func into a Result-returning helper. On success, returns
+ Result(data=None). The legacy _gui_func method proceeds to the rest
+ of the render loop.
+ """
+ from unittest.mock import MagicMock
+ import src.gui_2 as gui2_mod
+ app = MagicMock()
+ app.controller = MagicMock()
+ app.controller._init_start_ts = 1000.0
+ result = gui2_mod._gui_func_entry_log_result(app)
+ assert result.ok, f"Expected ok=True on success, got errors: {result.errors}"
+ assert result.data is None
+
+
+def test_phase_10_l1152_gui_func_entry_log_result_failure():
+ """
+ L1152 _gui_func_entry_log_result returns Result(data=None, errors=[ErrorInfo]) on failure.
+
+ When the sys.stderr.write or sys.stderr.flush raises (e.g., broken pipe),
+ the helper converts to ErrorInfo. The legacy _gui_func method drains to
+ self._last_request_errors and proceeds with the rest of the render loop
+ (preserving the original behavior of continuing past the failure).
+ """
+ from unittest.mock import MagicMock, patch
+ import src.gui_2 as gui2_mod
+ app = MagicMock()
+ app.controller = MagicMock()
+ app.controller._init_start_ts = 1000.0
+ with patch("src.gui_2.sys.stderr.write", side_effect=OSError("broken pipe")):
+  result = gui2_mod._gui_func_entry_log_result(app)
+ assert not result.ok, f"Expected ok=False on failure, got data: {result.data}"
+ assert result.data is None
+ assert result.errors, "Expected at least one error on failure"
+ err = result.errors[0]
+ assert err.source == "gui_2._gui_func_entry_log_result"
+ assert "broken pipe" in err.message
+
+