test(gui_2): add 2 Phase 10 invariant tests + Phase 10 checkpoint

TIER-2 READ conductor/code_styleguides/error_handling.md end-to-end before Phase 10.
ANTI-SLIMING VERIFIED: 13 INTERNAL_SILENT_SWALLOW sites migrated to Result[T].
logging NOT a drain per the user's principle 2026-06-17.

Invariant tests:
1. test_phase_10_invariant_silent_swallow_count_zero: verifies audit
   shows 0 INTERNAL_SILENT_SWALLOW sites in src/gui_2.py (was 13).
2. test_phase_10_invariant_all_13_sites_have_tests: verifies all 13
   sites have success and failure tests (>= 2 tests per site).

State updates:
- phase_10 = completed (was pending)
- silent_swallow_count_zero = true (was false)
- All 13 site tasks (t10_1 through t10_13) marked completed with SHAs
- t10_14 (this checkpoint commit) marked in_progress

29 Phase 10 tests pass: 27 site tests + 2 invariant tests.

tests/test_gui_2_result.py

@@ -2300,4 +2300,97 @@ def test_phase_10_l7315_ticket_id_max_int_result_failure():
  assert "invalid literal" in err.message or "T-abc" in err.message
 
 
+# =============================================================================
+# Phase 10 Invariant Tests (result_migration_gui_2_20260619)
+# Lock the per-phase progress: 13 INTERNAL_SILENT_SWALLOW sites migrated to
+# Result[T] with full propagation (NO narrowing+logging, NO pass-after-log).
+# logging NOT a drain per the user's principle 2026-06-17.
+# =============================================================================
+
+
+def test_phase_10_invariant_silent_swallow_count_zero():
+ """
+ Phase 10 invariant: the audit's INTERNAL_SILENT_SWALLOW count for src/gui_2.py
+ is now 0. All 13 sites in the inventory have been migrated to Result[T]
+ propagation. The new helpers are classified as INTERNAL_COMPLIANT (or
+ BOUNDARY_CONVERSION for the dispatcher wrappers), not as SILENT_SWALLOW.
+
+ Per the user's principle 2026-06-17 (logging NOT a drain), the
+ migration replaced each site with a full Result[T] pattern:
+ - Helper: returns Result(data=X, errors=[ErrorInfo]) on exception
+ - Wrapper: calls helper, drains errors to the appropriate data plane
+   (NOT silent swallow)
+ - Tests: 2 tests per site verify success + failure paths
+
+ Pre-Phase 10 baseline: 13. Post-Phase 10 baseline: 0. This test pins
+ the count to 0.
+ """
+ result = subprocess.run(
+  ["uv", "run", "python", "scripts/audit_exception_handling.py", "--src", "src", "--json"],
+  capture_output=True,
+  text=True,
+ )
+ assert result.returncode == 0, (
+  f"audit_exception_handling.py exited {result.returncode}; stderr:\n"
+  f"{result.stderr[:2000]}"
+ )
+ data = json.loads(result.stdout)
+ gui2 = [f for f in data.get("files", []) if "gui_2" in f.get("filename", "")][0]
+ silent_swallows = [f for f in gui2.get("findings", []) if f.get("category") == "INTERNAL_SILENT_SWALLOW"]
+ assert len(silent_swallows) == 0, (
+  f"Phase 10 invariant: expected 0 INTERNAL_SILENT_SWALLOW sites in src/gui_2.py "
+  f"(post-Phase 10 baseline; all 13 sites migrated to Result[T]); "
+  f"found {len(silent_swallows)}. Lines: {[f.get('line') for f in silent_swallows]}"
+ )
+
+
+def test_phase_10_invariant_all_13_sites_have_tests():
+ """
+ Phase 10 invariant: all 13 INTERNAL_SILENT_SWALLOW migration sites have
+ success and failure tests in this test file. Verifies the test coverage
+ for Phase 10 is complete.
+
+ The 13 sites (from PHASE1_SITE_INVENTORY.md):
+ - L216 _detect_refresh_rate_win32
+ - L241 _resolve_font_path
+ - L567 _post_init
+ - L683 run
+ - L974 shutdown
+ - L1074 _gui_func
+ - L1348 _close_vscode_diff
+ - L1504 render_main_interface (focus_response)
+ - L1530 render_main_interface (autosave)
+ - L4742 _on_warmup_complete_callback
+ - L6694 render_tier_stream_panel
+ - L7029 render_task_dag_panel (cycle_check)
+ - L7045 render_task_dag_panel (ticket_id_parse)
+ """
+ import re
+ text = Path(__file__).read_text(encoding="utf-8")
+ sites = [
+  ("L216", "detect_refresh_rate_win32"),
+  ("L264", "resolve_font_path"),
+  ("L612", "post_init_callback"),
+  ("L728", "run_immapp"),
+  ("L1052", "shutdown_save_ini"),
+  ("L1152", "gui_func_entry_log"),
+  ("L1466", "close_vscode_diff_terminate"),
+  ("L1647", "focus_response_window"),
+  ("L1693", "autosave_flush"),
+  ("L4911", "on_warmup_complete_callback"),
+  ("L6908", "tier_stream_scroll_sync"),
+  ("L7271", "dag_cycle_check"),
+  ("L7315", "ticket_id_max_int"),
+ ]
+ for line, site in sites:
+  # Allow either _result_success/_result_failure OR descriptive suffixes
+  pattern = rf"def test_phase_10_{line.lower()}_{site}_result_(\w+)\("
+  matches = re.findall(pattern, text)
+  assert len(matches) >= 2, (
+   f"Phase 10 invariant: missing tests for {line} {site}. "
+   f"Found {len(matches)} tests matching {pattern}. "
+   f"Need at least 2 (one success-like, one failure-like)."
+  )
+
+