fix: stop click handlers firing after long-press and drag-select

[eleboucher]

Description

Long-press on a room/space nav item opened the context menu, but the synthetic click that followed navigated and immediately dismissed it. Guard the click path with menu.consumeLongPressFired() (RoomNavItem, SpaceTabs).

Drag-selecting across an abbreviation or mention link fired click on mouseup, toggling the tooltip or navigating away and killing the selection. Guard those handlers with a collapsed-selection check (AbbreviationTerm, useMentionClickHandler) and make abbreviation text selectable on desktop only (mobile keeps userSelect:none so the long-press context menu isn't hijacked by the native callout).

Fixes #

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings

AI disclosure:

• Partially AI assisted (clarify which code was AI assisted and briefly explain what it does).
• Fully AI generated (explain what all the generated code does in moderate detail).