Sort the Files panel by last modified

[boom-bang]

Problem

The Files panel always lists entries in the tree's default order (folders first, then by name). When I use it to check what the agent just touched, the recently changed files sit somewhere in a long alphabetical list. I'd like to sort by last modified, newest first, like ls -lt or VS Code's explorer.sortOrder: "modified".

What I found

• ProjectEntry (packages/contracts/src/project.ts) is { path, kind, ignored? }, so the client has no timestamp to sort on.
• projects.listEntries (apps/server/src/workspace/WorkspaceEntries.ts) lists one directory per call with readdir(..., { withFileTypes: true }) and no stat.
• FileBrowserPanel.tsx builds the tree with useFileTree from @pierre/trees@1.0.0-beta.6. That option set accepts sort?: 'default' | FileTreeSortComparator. The comparator only sees basename, depth, isDirectory, path and segments, so it needs the mtime from a map the panel keeps itself.

Proposal

1. Add an optional mtimeMs to ProjectEntry.
2. Fill it in on the server only when the client asks for it, with bounded-concurrency stat calls. The default name order keeps today's single readdir fast path.
3. Add a name / last modified choice. A toggle in the panel header next to search and refresh would fit. A setting would also work.
4. Pass a comparator to useFileTree that orders by mtimeMs descending, with name as a stable tie-breaker.

Prior art in this repo

#2122 asked for the same ordering in the Add Project folder picker, and #5963 implemented it as a "Folder sort order" setting with ls -lt semantics and bounded-concurrency stats. #5963 was closed in the backlog sweep as stale, not rejected, so the approach may be reusable here. I couldn't find an existing issue, PR or discussion about the Files panel itself.

Open questions

• Is the Files panel the right place for this, or should it wait for the panel redesign?
• Setting, header toggle, or both?
• For folders, is the folder's own mtime good enough, or should it reflect the newest descendant? I'd start with its own mtime, as feat(web): folder picker can sort by last modified #5963 did.
• Does @pierre/trees re-sort in place when the comparator changes, or does the tree need a reset?

I'm happy to implement this if a maintainer approves the direction and scope first, as CONTRIBUTING.md asks.

---

This discussion was written on my behalf by Claude Sonnet 5.5, working from inside T3 Code.

[boom-bang]

Note

🤖 Claude Opus 5.5 responding on behalf of boom-bang

I've built this on a fork and would like a maintainer to approve the scope before I open a PR, as CONTRIBUTING.md asks.

Branch: main...boom-bang:t3code:feat/files-panel-sort

What it does

• Two icon buttons in the Files panel header, after the search field. One toggles the sort key between name (A-Z icon) and date modified (clock icon). The other toggles ascending and descending (arrow up or down).
• The default is name ascending, which keeps today's order exactly. A test checks the new comparator against @pierre/trees' own default order.
• Folders stay before files in every mode, like VS Code's explorer.sortOrder: "modified". A folder uses its own mtime.
• The choice is saved in localStorage under t3code:file-browser-sort.

Contract and server

• ProjectEntry gains an optional mtimeMs, and ProjectListEntriesInput gains an optional includeModifiedTimes.
• The server runs stat only when the panel sorts by date. Name mode keeps today's single readdir path. On a 40,000-file folder, name mode lists in about 30 ms on both main and this branch, and date mode takes about 700 ms.
• Switching to date sort lists the already-loaded folders again so their mtimes arrive.

One library quirk worth knowing
resetPaths(paths, { initialExpandedPaths }) finds each folder by walking siblings in the default order (path-store/src/store.js). Under a custom sort it stops early, so the panel reopens folders through item handles after a re-sort.

Scope check

1. Is a header toggle the right UI, or would you rather have a setting?
2. Is opt-in includeModifiedTimes on projects.listEntries acceptable, or would you prefer a different shape?

If the direction looks right, I'll open the PR with before and after screenshots and the test evidence.

[boom-bang]

Name A-Z (the default, same order as today)

Date modified, newest first