feat(tasks): add archive on merge

[janburzinski]

Description

• adds a setting to auto-archive when their pr is merged
• redirects away from archived/missing tasks to avoid stale task views
• auto-archive is off by default

Screenshot/Recording (if applicable)

https://streamable.com/co0i1k

Checklist

• I kept this PR small and focused
• I ran a self-review before opening this PR
• I ran the relevant local checks or explained why not
• I updated docs when behavior or setup changed
• I added or updated tests when behavior changed, or explained why not
• I only added comments where the logic is not obvious
• I used Conventional Commits for commit
  messages and, when possible, the PR title

[greptile-apps]

Greptile Summary

Adds an opt-in "Archive on merge" setting that automatically archives a task when its PR is detected as merged, and redirects away from archived/missing task views to prevent stale UI states. The feature is off by default.

• task-manager.ts: Two detection paths — prUpdatedChannel (real-time) and _reloadPrsForTask (batch sync). Both include a double-archive guard (task.archivedAt checked before and after the async settings fetch), error handling, and navigation only after the archive RPC resolves. The sync path additionally filters for PRs that transitioned to merged to avoid retroactive archiving of old tasks.
• view.tsx: canActivate now redirects to the project view when a task is archived or missing; auto-provision is also gated on archivedAt to avoid provisioning archived tasks.
• Settings plumbing (schema.ts, settings-registry.ts, useTaskSettings.ts, TaskSettingsRows.tsx, SettingsPage.tsx): Follows the established pattern for boolean task settings with default-off, reset-to-default button, and toggle switch.

Confidence Score: 5/5

Safe to merge — the core archive logic is well-guarded against double-archiving and retroactive archiving, navigation fires only after the archive RPC resolves, and the view guard cleanly prevents stale task views.

The previously flagged concerns (double-archive race, premature navigation, retroactive archiving of old merged tasks, unhandled rejection in the sync path) are all addressed in this revision. The one remaining note — that a PR first observed as already-merged is invisible to the batch-sync archive path — is a minor edge case with limited user impact, not a defect in the happy path.

No files require special attention; task-manager.ts carries the most logic complexity but it is sound.

Important Files Changed

Filename	Overview
apps/emdash-desktop/src/renderer/features/tasks/stores/task-manager.ts	Core archive-on-merge logic: double-archive guard added, navigation moved after archive RPC, newlyMergedPrs filter prevents retroactive archiving, error handling added — but newly-added already-merged PRs are invisible to the sync path.
apps/emdash-desktop/src/renderer/features/tasks/view.tsx	Adds archivedAt guard to canActivate so navigating to an archived task redirects to the project view; also guards auto-provision from running on archived tasks.
apps/emdash-desktop/src/renderer/features/tasks/hooks/useTaskSettings.ts	Extends TaskSettingsModel and the hook return with archiveOnMerge, updateArchiveOnMerge, and resetArchiveOnMerge — mirrors existing field patterns correctly.
apps/emdash-desktop/src/renderer/features/settings/components/TaskSettingsRows.tsx	Adds ArchiveOnMergeRow component following the same pattern as other settings rows (reset button + toggle switch), no issues.
apps/emdash-desktop/src/renderer/features/settings/components/SettingsPage.tsx	Registers the new ArchiveOnMergeRow in the task settings section — mechanical wiring, no issues.
apps/emdash-desktop/src/main/core/settings/schema.ts	Adds archiveOnMerge: z.boolean() to taskSettingsSchema — straightforward schema addition, no issues.
apps/emdash-desktop/src/main/core/settings/settings-registry.ts	Adds archiveOnMerge: false as default — correctly defaults the feature off, consistent with other boolean task settings.

Sequence Diagram

sequenceDiagram
    participant E as Event Bus
    participant TM as TaskManagerStore
    participant RPC as rpc
    participant Nav as Navigation

    Note over E,Nav: Path 1 — real-time prUpdatedChannel
    E->>TM: "prUpdatedChannel({ pr })"
    TM->>TM: update task.prs (runInAction)
    TM->>TM: _archiveTaskIfMerged(task, [pr])
    TM->>TM: check task.archivedAt (guard 1)
    TM->>RPC: appSettings.get('tasks')
    RPC-->>TM: settings
    TM->>TM: check task.archivedAt + archiveOnMerge (guard 2)
    TM->>RPC: tasks.archiveTask(projectId, taskId)
    RPC-->>TM: success
    TM->>Nav: _leaveTaskViewAfterArchive(taskId)

    Note over E,Nav: Path 2 — prSyncProgressChannel (batch sync)
    E->>TM: "prSyncProgressChannel({ status: 'done' })"
    TM->>RPC: pullRequests.getPullRequestsForTask(...)
    RPC-->>TM: prs (current state)
    TM->>TM: snapshot previousPrStatuses
    TM->>TM: update task.prs (runInAction)
    TM->>TM: compute newlyMergedPrs (transition filter)
    TM->>TM: _archiveTaskIfMerged(task, newlyMergedPrs)
    TM->>RPC: tasks.archiveTask(projectId, taskId)
    RPC-->>TM: success
    TM->>Nav: _leaveTaskViewAfterArchive(taskId)

    Note over E,Nav: canActivate guard (on navigation)
    Nav->>TM: "canActivate({ projectId, taskId })"
    TM->>TM: check taskStore exists + archivedAt
    TM-->>Nav: redirect to project if archived/missing

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Prompt To Fix All With AI

Fix the following 1 code review issue. Work through them one at a time, proposing concise fixes.

---

### Issue 1 of 1
apps/emdash-desktop/src/renderer/features/tasks/stores/task-manager.ts:286-291
**Newly-added merged PRs bypass archive in the sync path**

`newlyMergedPrs` requires `previousPrStatuses.get(pr.url) !== undefined`, so a PR that is first observed in `merged` state (e.g., the user manually links an already-merged PR, or the app starts up and the first sync response already shows it as `merged`) will not trigger auto-archive from the `_reloadPrsForTask` path. The `prUpdatedChannel` path has no such restriction and would handle it there, but only if a live push event is received for that PR after it was linked. If the PR was merged before it was first tracked, the merge is permanently invisible to the sync path.

_{Reviews (3): Last reviewed commit: "fix(tasks): handle PR sync archive error..." | Re-trigger Greptile}

[janburzinski]

@greptileai

[janburzinski]

@greptileai