* Fix custom emoji shortcode matching to include dashes
The regex pattern for matching NIP-30 custom emoji shortcodes was missing
the dash character, causing emojis like :work-out: to fail matching.
Updated both ReactionRenderer and ReactionCompactPreview to use
[a-zA-Z0-9_-] instead of [a-zA-Z0-9_].
* Refactor: extract emoji shortcode regex to constant
Move the emoji shortcode matching pattern to EMOJI_SHORTCODE_REGEX
constant in emoji-helpers.ts for reuse across reaction renderers.
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Co-authored-by: Claude <noreply@anthropic.com>