Plan: Replan/Restart Must Invalidate Cached Plan and PR Association#

Summary#

When /agent replan or /agent restart fires, cached plan artefacts and PR associations must be invalidated so the next run generates a fresh plan and opens a new PR. Currently, replan clears prNumber/prBranch but does not clear plan artefacts or track attempt count; restart does not clear PR state at all.

Files#

File	Action	Description
`src/database/entities/task.entity.ts`	modify	Add `replanAttempt` column (integer, default 0)
`src/task-state/task-state.service.ts`	modify	Add `resetForReplan()` method that clears PR state, increments `replanAttempt`, and resets phases
`src/directive/directive.service.ts`	modify	Use `resetForReplan()` for replan; clear PR state for restart; add `replan_attempt` telemetry; close open PR with superseded message
`src/artefacts/artefacts.service.ts`	modify	Add `clearPlanArtefacts(taskDir)` to remove plan/*.md/json files on replan
`src/task-state/task-state.service.spec.ts`	modify	Add unit tests for `resetForReplan()`
`src/directive/directive.service.spec.ts`	modify	Add tests: replan invalidates plan cache, replan forces new PR branch, restart clears PR state

Steps#

Add replanAttempt to TaskEntity — new nullable integer column with default 0, snake_case replan_attempt.
Add resetForReplan() to TaskStateService — calls resetForRestart(), then nullifies prNumber/prBranch, increments replanAttempt.
Add clearPlanArtefacts() to ArtefactsService — removes files in {taskDir}/plan/ directory (plan.md, context.json, prd.json).
Update DirectiveService replan handler — use resetForReplan() instead of manual field clearing; call clearPlanArtefacts(); record replan_attempt event with attempt number; post superseded comment on open PR before closing.
Update DirectiveService restart handler — clear prNumber/prBranch (currently missing); post superseded comment on open PR if exists.
Add unit tests — cover: resetForReplan() clears PR + increments counter; replan clears plan artefacts; restart clears PR state; no-op when no prior artefacts; replan_attempt telemetry recorded.

Verification#

npm run test passes with new unit tests covering replan invalidation, restart PR clearing, and idempotent no-op cases.
npm run lint passes with zero warnings.
Manually verify: after replan, task.prNumber === null, task.prBranch === null, task.replanAttempt incremented, plan directory cleared.

Risks#

SQLite migration: Adding replanAttempt column with DEFAULT 0 is safe for TypeORM synchronize mode, but if the project uses explicit migrations, a migration file may be needed.
Restart scope expansion: Adding PR cleanup to restart changes existing behavior — the issue explicitly requires it, but it's a behavioral change to flag in the PR.