fix: guard task status updates on invoice lifecycle transitions

Prevent overwriting task status when task has moved to a new revision
cycle after being invoiced. Now uses .eq('status', guardStatus) to only
update tasks still at the expected prior state:
- invoice creation: only update tasks at client_approved → invoiced
- mark sent: only client_approved → invoiced
- mark paid: only invoiced → paid
- reopen: only paid → client_approved

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

.claude/settings.local.json

@@ -24,7 +24,8 @@
       "mcp__plugin_supabase_supabase__execute_sql",
       "Bash(sed -n '88,100p' src/pages/Tasks.jsx)",
       "Bash(sed -n '570,600p' src/pages/Tasks.jsx)",
-      "Bash(git commit -q -m 'fix: hide counter on All tab in projects table *)"
+      "Bash(git commit -q -m 'fix: hide counter on All tab in projects table *)",
+      "Bash(git commit -q -m 'fix: guard task status updates on invoice lifecycle transitions *)"
     ]
   }
 }