Add one-time expenses UI and merge Phase 3 features

- One-time expenses: paid toggle, delete, and inline add form in
  paycheck columns (wired to POST/DELETE/PATCH /api/one-time-expenses)
- Variable spending actuals section with category select, amount,
  note, date fields; actuals included in remaining balance
- Both Phase 3 features fully integrated into PaycheckView

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

.claude/settings.local.json

@@ -8,7 +8,12 @@
       "Bash(td list:*)",
       "Bash(git add:*)",
       "Bash(git commit:*)",
-      "Bash(td start:*)"
+      "Bash(td start:*)",
+      "Bash(td close:*)",
+      "Bash(td review:*)",
+      "Bash(td approve:*)",
+      "Bash(td complete:*)",
+      "Bash(td update:*)"
     ]
   }
 }