fix(01-foundation): revise plans based on checker feedback

- 01-03: wave 2 → wave 3 (depends on 01-02 which is also wave 2; must be wave 3)
- 01-06: add ProgressUpdatedMessage.cs to files_modified; add third StatusBarItem (progress %) to XAML per locked CONTEXT.md decision; add ProgressUpdatedMessage subscription in MainWindowViewModel.OnActivated()
- 01-08: add comment to empty <files> element (auto task with no file output)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.planning/phases/01-foundation/01-03-PLAN.md

@@ -2,7 +2,7 @@
 phase: 01-foundation
 plan: 03
 type: execute
-wave: 2
+wave: 3
 depends_on:
   - 01-01
   - 01-02