feat(db): 0013 tasks tables and 0014 agent_run_event; tasks uses db migrations

tasks_run_meta/tasks_fact/tasks_op_ledger move into packages/db (if not exists, old
tasks_migration tables dropped); packages/tasks/migrations and migrateTasksTables
removed, tests migrate their schema with @umt/db. agent_run_event(run_id, seq, type,
at, payload) with (run_id, seq) primary key; types regenerated, db-sync covers it.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

packages/tasks/src/index.ts

@@ -26,7 +26,6 @@ export {
   silentSink,
   type TaskLogger,
 } from "./logger.ts";
-export { migrateTasksTables, TASKS_MIGRATIONS_DIR } from "./migrate.ts";
 export {
   type AttemptInfo,
   assertAttemptToken,