Release Discord Announcement Skill

Write the Discord release announcement for the stable Paperclip release.

This is the companion to .agents/skills/release-changelog/SKILL.md. That skill writes the changelog — during the beta soak it lives at releases/beta/v{beta-version}.md on the release-notes/v{beta-version} branch, and after the stable ships a canonicalization PR renames it to releases/vYYYY.MDD.P.md (see that skill's Channel Process section). This skill turns that file into a single copy-pasteable Discord block, in dotta's voice, and posts it as the discord_announcement document on the release issue.

What dotta said

This is for discord — try to follow my format. If I have a section where I think about the future, pull from recent issues we're working on etc.