feat: implement AI checkpoint and task suggestion UI with approval flow

src/main/db/index.ts

@@ -32,6 +32,8 @@ const MIGRATION_SQL = `
     priority TEXT NOT NULL DEFAULT 'medium',
     assignee TEXT,
     due_date INTEGER,
+    is_ai_suggested INTEGER NOT NULL DEFAULT 0,
+    is_approved INTEGER NOT NULL DEFAULT 1,
     created_at INTEGER NOT NULL
   );
 
@@ -79,6 +81,10 @@ export function initDb(): DbInstance {
   // Run non-destructive migrations on every start
   sqlite.exec(MIGRATION_SQL);
 
+  // Additive column migrations (SQLite has no ADD COLUMN IF NOT EXISTS)
+  try { sqlite.exec('ALTER TABLE tasks ADD COLUMN is_ai_suggested INTEGER NOT NULL DEFAULT 0'); } catch { /* already exists */ }
+  try { sqlite.exec('ALTER TABLE tasks ADD COLUMN is_approved INTEGER NOT NULL DEFAULT 1'); } catch { /* already exists */ }
+
   dbInstance = drizzle(sqlite, { schema });
   return dbInstance;
 }