feat(web): swipe session rows to archive or delete on touch

[btli]

Related issue

N/A

Summary

Session rows in the left panel had no touch-friendly quick actions — on
mobile you had to open the kebab to archive or delete. This adds a
configurable horizontal swipe gesture on each row:

• Swipe a row left or right to run an action. Each direction independently
  maps to Archive, Delete, or None, persisted per-device.
• Configure it in Settings → Appearance → Swipe actions (two selects,
  one per direction). Defaults: swipe-left → Archive, swipe-right → None.
• Swipe→archive reuses the kebab's existing stop-then-archive handler;
  swipe→delete opens the same delete confirm dialog the kebab uses (no
  immediate delete, no separate undo path). "None" is inert.
• Coexists with the existing dnd-kit drag-to-project: the swipe locks by
  axis (horizontal past a threshold) and yields to the long-press drag, so
  drag-to-file-into-project is unaffected. Gated to touch/mobile so desktop
  hover controls don't regress.

Test Plan

Run in web/ (Node 20):

• npm run type-check — clean
• npm run lint — no new issues in changed files (pre-existing warnings/errors only)
• npm run test — 4099 passed | 3 expected fail | 2 skipped
• npm run format:check — all files match Prettier style

New/updated tests:

• web/src/lib/swipeActionPreferences.test.ts — read/write/validate/defaults round-trip.
• web/src/shell/Sidebar.rowActions.test.tsx — swipe→archive drives the
  stop→archive handler; swipe→delete opens the confirm dialog (deletes only
  after confirm); "none" is inert; both-directions-same-action; sub-threshold
  swipe is a no-op; desktop ignores the gesture. Driven with
  fireEvent.pointerDown/Move/Up since jsdom has no real touch.

Demo

Recorded on a mobile viewport (touch emulation). The clip shows: opening
Settings → Appearance → Swipe actions and setting Swipe left → Archive
and Swipe right → Delete, then back on the session list a swipe-left
archives a row (it slides over the archive hint and leaves the list), and a
swipe-right on another row opens the Delete confirmation dialog — delete
stays gated behind confirm, never immediate.

Download MP4

Type of change

• Bug fix
• Feature
• UI / frontend change
• Refactor / chore
• Docs
• Test / CI
• Breaking change

Test coverage

• Unit tests added / updated
• Integration tests added / updated
• E2E tests added / updated
• Manual verification completed
• Existing tests cover this change
• Not applicable

Coverage notes

Behavior is covered by unit tests (preference round-trip + swipe gesture via
synthetic pointer events). The live touch gesture / visual affordance is shown in the Demo section above.

Changelog

Swipe left or right on a session row (touch devices) to archive or delete it, configurable in Settings → Appearance.

This pull request and its description were written by Isaac.

[github-actions]

@btli This PR is a Bug fix, Feature, or UI / frontend change but the Demo section is missing or only contains a placeholder.

These change types require a screenshot or screen recording so reviewers can see the new behaviour without checking out the branch. Please update the Demo section with:

• A screenshot or screen recording of the change, or
• A link to a hosted video or GIF showing the new behaviour.

Use N/A only when the change has no user-visible effect whatsoever (e.g. a pure refactor or test-only change). If that's the case, uncheck the relevant type box and check Refactor / chore or Test / CI instead.

[fanzeyi]

Hi, thanks for working on this. There are a few issues with this PR:

• There are now background color for each row in the session:

• The icons location are incorrect in small screen (included in the screenshot above, the unread indicator).
• When swiping, the icon is now overlapping with the session content itself:

[fanzeyi]

comment above

[github-actions]

Closing this PR because it has been labeled waiting-on-author for 7 days without an author reply or new commit.

The label was last applied on 2026-07-26T23:17:55Z. If you are ready to continue, please reopen this PR or open a new one.

[btli]

Continued in #3985 — I don't have permission to reopen this one, so the work landed in a fresh PR against current main.

@fanzeyi all three points from your review are fixed there:

• Row background colors — the translating wrapper had an unconditional bg-sidebar, which plated every row at rest (desktop included). It now paints only while a swipe is in progress: at rest backgroundColor reads rgba(0, 0, 0, 0).
• Icon positions on small screens — the session-state badge and the pin/kebab are absolutely positioned and were sitting outside the translating wrapper. All row content now shares one layout-neutral surface; measured in a real browser, the wrapper rect is identical to the <li> (left 9, right 400.5, top 292.5, height 36), so nothing moves at rest.
• Icon overlapping the session content mid-swipe — that was the same root cause: the icons did not translate, so the text slid under them. They now travel with the row (kebab 369 → 273, exactly the −96px swipe), and the reveal hint sits in the gap the swipe opens — hint icon at 362–385 vs the row edge at 304.5, so no overlap.

#3985 has the demo recorded against the running app, plus the geometry readings behind those numbers. A second review pass also turned up a real gesture bug — a fast flick could commit off a stale offset and either miss the archive or fire when you had pulled back — fixed there with a regression test.