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

[btli]

Related issue

N/A

Supersedes #3154 (auto-closed after 7 days on waiting-on-author; I don't
have permission to reopen it, hence a fresh PR). This carries the same feature
plus fixes for every point @fanzeyi raised in that review, rebased onto current
main. See Review feedback from #3154 below for the point-by-point.

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 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.

The whole row — link, session-state badge, and pin/kebab controls — moves as one
surface, so trailing icons travel with the text rather than the text sliding out
from under them. The row insets from the swiped edge rather than translating:
revealing the hint needs ~48px of gap but the title only has ~18px of slack
before the panel boundary, so a translate would cut the title mid-word. An inset
lets the title re-truncate with its existing ellipsis and keeps every control
inside the panel. All swipe-only markup and styling is gated on an in-progress
swipe, so a row at rest renders exactly as it did before this change.

Review feedback from #3154

All three points, verified in a real browser at a 414×800 touch viewport (numbers
are getBoundingClientRect / getComputedStyle readings from the running app):

Feedback	Fix	Measured
"There are now background color for each row in the session"	The row wrapper had an unconditional bg-sidebar, plating every row at rest — desktop included. It now paints only mid-swipe.	At rest backgroundColor: rgba(0, 0, 0, 0); mid-swipe rgb(253, 250, 250)
"The icons location are incorrect in small screen" (unread indicator)	The badge and pin/kebab are absolutely positioned; they sat outside the moving wrapper. All row content now shares one layout-neutral surface.	Wrapper rect identical to the <li> at rest: left 9, right 400.5, top 292.5, height 36
"When swiping, the icon is now overlapping with the session content itself"	Because the icons didn't move with the row, text slid under them. Row content now moves as one surface and the reveal hint occupies the space the row vacates, so the two never share pixels.	Swiping left, the row's right edge insets 400.5 → 325.8 and the kebab travels with it (369 → 294.3); the hint sits in the vacated strip

Additional hardening

A second review pass (Codex, gpt-5.6-sol) found issues beyond the original
feedback, fixed in the follow-up commits:

• Commit off a synchronously-tracked offset, not the rendered dx. A fast
  flick can lift the finger before React commits the render for the final
  pointermove, so the action was decided from a stale offset — a swipe past the
  threshold could fail to fire, and one that snapped back under it could fire
  anyway. Covered by a regression test that fails on the old code.
• touch-pan-y where a swipe can fire, so the browser can't claim the
  horizontal pan (or a back-navigation gesture) and cancel the drag mid-swipe.
  Vertical scrolling stays native.
• Ignore pointerdowns that bubbled out of a portal. The row's dialogs are
  React children rendered in portals, so a drag inside the open delete dialog
  would otherwise start a swipe on the row behind it.
• "Reset appearance" resets the swipe preference, which it promises to do for
  every appearance choice.
• Transitions only at rest, so the row tracks the finger 1:1 while swiping
  instead of easing behind it.
• The hint glyph scales and its tint deepens past the commit point, so "will fire
  on release" isn't signalled by color alone.
• The archive reveal uses the accent pair rather than --primary, which is
  near-black in light mode and rendered the hint as a flat grey block that read
  as a disabled button instead of a revealed surface.
• Travel past the commit point is damped to a third and hard-capped, so a long
  drag resists rather than pulling the row further than the action needs.

Test Plan

Run in web/ (Node 20 — Node 26 breaks jsdom's localStorage):

• npm run type-check — clean
• npm run lint — clean (exit 0)
• npm run test — 4907 passed | 3 expected fail | 1 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 and non-touch pointers ignore the gesture; vertical drags yield
  to scroll; dnd-kit takes over mid-gesture; a fast flick that releases before
  the last move renders still commits, and one that snaps back under the
  threshold does not; portal-bubbled pointerdowns are ignored; travel tracks 1:1
  to the commit point then damps and caps, so the title can't be pulled out of
  the panel.

Manual verification drove the real app (spawned omnigent server + runner) with
CDP touch events — page.mouse sends pointerType: "mouse", which the gesture
ignores by design — and read back live geometry for the table above.

Demo

Recorded against the running app on a 414×800 touch viewport. The clip shows
Settings → Appearance → Swipe actions with swipe-left → Archive and
swipe-right → Delete, then back on the session list: a swipe-left archives a
row (it insets to reveal the archive hint, then leaves the list), and a
swipe-right on another row opens the Delete confirmation dialog — delete
stays gated behind confirm, never immediate.

Download MP4

Stills — note the rows at rest carry no background plate, and the kebab travels
with the row mid-swipe:

Settings	Rows at rest	Mid-swipe (archive)	Mid-swipe (delete)	Delete confirm
settings	at rest	archive	delete	confirm

The row title stays fully inside the panel throughout — measured left: 18 at
rest and mid-swipe alike — and truncates with an ellipsis when the inset narrows
it, rather than being clipped by the panel edge.

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: the preference round-trip, and the gesture
state machine driven with synthetic pointer events (including the fast-flick and
snap-back cases that jsdom's render timing would otherwise mask). The live touch
gesture, the at-rest/mid-swipe geometry, and the visual affordance were verified
against the running app in a real browser — see Test Plan and the Demo 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.

[btli]

Pushed 2 commits closing the review's coverage gaps:

• The Settings direction mapping is covered end to end (a swapped [direction] write now fails a test), along with reveal/action pairing, the exact 72px commit boundary, single dispatch, and a throwing localStorage getter.
• One small runtime change: unrecognized stored actions normalize to none instead of silently arming archive.

Each new test was mutation-verified against the specific defect it guards.

---

Recommended merge order — this PR is one of seven fixed and verified together; the fully integrated reference (all cross-PR conflicts resolved, 5,003 web tests + 273/273 Android tests green) is btli:test-android-ui-integration @ 3fa45ff3.

Android track (suggest landing first — security fixes, and the later two resolve against it):

1. fix(android): sign in to servers behind front-door auth proxies (Databricks Apps) #3800 — no dependencies
2. fix(web): keep the Workspace rail clear of the OS status and nav bars #3587 — rebase after fix(android): sign in to servers behind front-door auth proxies (Databricks Apps) #3800: it picks up applySystemBarContrast(Configuration), which fixes this branch's one pre-existing Robolectric failure; and since main now has flush rails (feat(web): make the rails flush boxes and move the canvas gradient #4020), the rebase should also drop the stale +16 from --workspace-panel-offset (see integration commit 8b687d7c)
3. fix(android): keep the server switcher centred over the chat column, clear of header controls #3589 — after fix(android): sign in to servers behind front-door auth proxies (Databricks Apps) #3800: both add constructor callbacks to OmnigentBridgeListener; union them (resolution in integration merge 3fa45ff3)

Web track (file-disjoint from the Android track; order within it matters):
4. #3985 — base swipe-actions feature
5. #4060 — folder context menu
6. #4057 — mobile ungroup drop zone
7. #4065 — hold: superseded by the unified row-gesture recognizer, which builds on #3985 and interacts with #4057/#4060; after 4–6 land, update it to the recognizer commits (69a8ada5, bf597b87, e388aacf, reachable on the integration branch)