Release v0.51.310 — Release JZ (#3760 — long-press project chips to manage on touch) (#3767)

* feat(sidebar): long-press project chips to open the context menu on touch (#3760)

Project filter chips could only be deleted/renamed via the right-click context
menu (oncontextmenu), which has no touch equivalent — so mobile/tablet users had
no way to delete a project from the sidebar; the list grew forever.

Adds a 500ms long-press gesture mirroring the existing session-item long-press
pattern: touchstart schedules the menu, touchmove cancels on >10px drift,
touchend suppresses the synthetic click when the long-press fired, touchcancel
cleans up. `.project-chip.long-pressing` gives accent + slight-scale feedback;
`touch-action:manipulation` + `user-select:none` + `-webkit-touch-callout:none`
prevent the native callout/selection from competing.

Maintainer fix on top of the contributor PR (multi-touch correctness, flagged in
review): touchstart now clears any in-flight `_lpTimer` before scheduling a new
one (a second finger / stray touchstart previously orphaned the prior timer,
which then fired unsuppressed ~500ms later and popped the menu after the gesture
was cancelled), and the timer body bails if `_lpHandled` is already set so a
stale fire is a no-op — matching the session-item belt-and-suspenders. Also
dropped a stale, unrelated issue reference from the original comment.

Co-authored-by: reinocheong <[email protected]>

* docs(changelog): stamp v0.51.310 — Release JZ (stage-3760 long-press project chips)

---------

Co-authored-by: nesquena-hermes <[email protected]>

CHANGELOG.md

@@ -3,6 +3,11 @@
 
 ## [Unreleased]
 
+## [v0.51.310] — 2026-06-07 — Release JZ (stage-3760 — long-press project chips to delete on touch)
+
+### Fixed
+- **Project chips can now be managed on touch devices.** The project filter chips in the sidebar exposed Rename / Color / Delete only through the right-click context menu, which has no touch equivalent — so on phones/tablets there was no way to delete a project and the list grew forever. A 500ms long-press now opens the same context menu (mirroring the existing session-item long-press): a >10px drag cancels it, a short tap still filters, and the synthetic click after the press is suppressed. The chip shows accent + slight-scale feedback while held, and native callout/selection is disabled so it doesn't compete with the gesture. Includes a multi-touch correctness fix (a second finger / stray touchstart can no longer orphan the press timer and pop the menu after the gesture was cancelled). Verified live: long-press opens the menu once, short tap doesn't, and the multi-touch-then-cancel case no longer fires. (#3760, @reinocheong)
+
 ## [v0.51.309] — 2026-06-07 — Release JY (stage-a5b — restore reconnect replays live tool cards)
 
 ### Fixed