55cf1fb0a4
- mention.ts: detectMention (cursor-aware), extractContent (parse @Name → UUID), renderBody (XSS-safe: escape-first then inject anchor tags, replaceAll for all occurrences)
- 19 unit tests in mention.spec.ts (all green)
- MentionEditor.svelte: textarea with @-trigger popup, debounced /api/users/search, keyboard navigation (↑↓ Enter Esc), Ctrl+Enter submit, @ button for accessibility
- CommentThread.svelte: replace plain textareas with MentionEditor, send mentionedUserIds on post/reply/edit, render comment bodies with {@html renderBody(...)}
- types.ts: add MentionDTO, add optional mentionDTOs to Comment and CommentReply
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>