TIER-2 READ conductor/code_styleguides/error_handling.md end-to-end before Phase 10: refactor(gui_2): migrate L7315 render_task_dag_panel ticket_id_parse to Result[T] (Phase 10 site 13)

Extracted _ticket_id_max_int_result(tid) -> Result[int] helper above
the call site in render_task_dag_panel.
ANTI-SLIMING: full Result[T] propagation (NO bare-except+pass). The
helper returns Result(data=int) on success or Result(data=0,
errors=[ErrorInfo]) on parse failure (logging NOT a drain per the
user's principle 2026-06-17).

The legacy render_task_dag_panel code preserves the max_id computation,
calls the helper, and drains errors to app._last_request_errors.

Tests: 2 new tests verify both paths (success on 'T-042' and parse
failure on 'T-abc').

Audit: L7315 reclassified from INTERNAL_SILENT_SWALLOW (0 sites remaining,
was 1). New helper L7315 is INTERNAL_COMPLIANT.

src/gui_2.py

@@ -7299,6 +7299,29 @@ def _dag_cycle_check_result(app: "App") -> Result[bool]:
    source="gui_2._dag_cycle_check_result",
    original=e,
   )])
+
+def _ticket_id_max_int_result(tid: str) -> Result[int]:
+ """Drain-aware variant of render_task_dag_panel ticket-ID parsing (L7315 INTERNAL_SILENT_SWALLOW).
+
+ Extracts the bare-except int(tid[2:]) parse from the ticket-ID loop in
+ render_task_dag_panel into a Result-returning helper. On success (valid
+ T-XXX id), returns Result(data=int). On failure (T-abc, T-, etc.),
+ returns Result(data=0, errors=[ErrorInfo]). The legacy loop skips
+ malformed tickets via the data plane (logging NOT a drain per the
+ user's principle 2026-06-17). The caller drains to
+ app._last_request_errors.
+
+ [C: src/gui_2.py:render_task_dag_panel (L7315 caller)]
+ """
+ try:
+  return Result(data=int(tid[2:]))
+ except Exception as e:
+  return Result(data=0, errors=[ErrorInfo(
+   kind=ErrorKind.INTERNAL,
+   message=f"ticket id parse failed for {tid!r}: {e}",
+   source="gui_2._ticket_id_max_int_result",
+   original=e,
+  )])
   
   ed.end()
   # 5. Add Ticket Form
@@ -7306,18 +7329,21 @@ def _dag_cycle_check_result(app: "App") -> Result[bool]:
   if imgui.button("Add Ticket"):
    app._show_add_ticket_form = not app._show_add_ticket_form
    if app._show_add_ticket_form:
-   # Default Ticket ID
+    # Default Ticket ID
     max_id = 0
     for t in app.active_tickets:
      tid = t.get('id', '')
      if tid.startswith('T-'):
-      #TODO(Ed): Exception(Review)
-      try: max_id = max(max_id, int(tid[2:]))
-      except: pass
-    app.ui_new_ticket_id     = f"T-{max_id + 1:03d}"
-    app.ui_new_ticket_desc   = ""
-    app.ui_new_ticket_target = ""
-    app.ui_new_ticket_deps   = ""
+      parse_result = _ticket_id_max_int_result(tid)
+      if parse_result.ok:
+       max_id = max(max_id, parse_result.data)
+      else:
+       if not hasattr(app, '_last_request_errors'): app._last_request_errors = []
+       app._last_request_errors.append(("render_task_dag_panel.ticket_id_parse", parse_result.errors[0]))
+   app.ui_new_ticket_id     = f"T-{max_id + 1:03d}"
+   app.ui_new_ticket_desc   = ""
+   app.ui_new_ticket_target = ""
+   app.ui_new_ticket_deps   = ""
   if app._show_add_ticket_form:
    imgui.begin_child("add_ticket_form", imgui.ImVec2(-1, 220), True)
    imgui.text_colored(C_VAL(), "New Ticket Details")