feat(push-task): connect notification module with task module

- Add task_type to w_push_events table and GORM models.
- Implement OnTaskCompleted callback hook in task executor to avoid circular dependencies.
- Implement task listener in push package to trigger notifications on task completion.
- Automatically resolve User objects from payload and results.
- Enhance UI to select task completed events and preview default templates.
- Update Swagger documentation.

internal/db/migrator/goose/postgres/202606150001_add_task_type_to_push_events.sql

@@ -0,0 +1,7 @@
+-- +goose Up
+ALTER TABLE w_push_events ADD COLUMN task_type VARCHAR(100) NOT NULL DEFAULT '';
+CREATE INDEX idx_w_push_events_task_type ON w_push_events(task_type);
+
+-- +goose Down
+DROP INDEX IF EXISTS idx_w_push_events_task_type;
+ALTER TABLE w_push_events DROP COLUMN task_type;

internal/db/migrator/goose/sqlite/202606150001_add_task_type_to_push_events.sql

@@ -0,0 +1,9 @@
+-- +goose Up
+ALTER TABLE w_push_events ADD COLUMN task_type VARCHAR(100) NOT NULL DEFAULT '';
+CREATE INDEX idx_w_push_events_task_type ON w_push_events(task_type);
+
+-- +goose Down
+DROP INDEX IF EXISTS idx_w_push_events_task_type;
+-- SQLite does not support DROP COLUMN in older versions easily, but standard ALTER TABLE DROP COLUMN works in SQLite 3.35.0+.
+-- We can write standard DROP COLUMN.
+ALTER TABLE w_push_events DROP COLUMN task_type;