fix monitor desktop unknown recovery

server/migrations/20260422120000_add_monitor_phase2_desktop_task_fields.up.sql

@@ -54,4 +54,4 @@ CREATE UNIQUE INDEX IF NOT EXISTS uq_desktop_tasks_monitor_active
     ON desktop_tasks (monitor_task_id)
     WHERE kind = 'monitor'
       AND monitor_task_id IS NOT NULL
-      AND status IN ('queued', 'in_progress', 'unknown');
+      AND status IN ('queued', 'in_progress');

server/migrations/20260622152000_fail_monitor_unknown_tasks.down.sql

@@ -0,0 +1,7 @@
+DROP INDEX IF EXISTS uq_desktop_tasks_monitor_active;
+
+CREATE UNIQUE INDEX IF NOT EXISTS uq_desktop_tasks_monitor_active
+    ON desktop_tasks (monitor_task_id)
+    WHERE kind = 'monitor'
+      AND monitor_task_id IS NOT NULL
+      AND status IN ('queued', 'in_progress', 'unknown');

server/migrations/20260622152000_fail_monitor_unknown_tasks.up.sql

@@ -0,0 +1,13 @@
+UPDATE desktop_tasks
+SET status = 'failed',
+    updated_at = NOW()
+WHERE kind = 'monitor'
+  AND status = 'unknown';
+
+DROP INDEX IF EXISTS uq_desktop_tasks_monitor_active;
+
+CREATE UNIQUE INDEX IF NOT EXISTS uq_desktop_tasks_monitor_active
+    ON desktop_tasks (monitor_task_id)
+    WHERE kind = 'monitor'
+      AND monitor_task_id IS NOT NULL
+      AND status IN ('queued', 'in_progress');