Subtext 2.1.0

Subtext 2.1.0, featuring multiple conversations, multimedia conversations, and more.

What's Changed

• Chatbook: modernize the chat story format (rewrite, redesign, new narrative features) by @samplereality in #4
• Docs site with auto-deploy to GitHub Pages + Snowman 2.1.2 parity audit by @samplereality in #5
• Redesign the icon as a modern chat mark by @samplereality in #6
• Add Snowman utility functions: either, hasVisited, visited, and more by @samplereality in #7
• Claude/trilogue relog modernize e8uleh by @samplereality in #8
• Catching up to main's readme by @samplereality in #9
• Claude/trilogue relog modernize e8uleh by @samplereality in #10
• Rename the story format from Chatbook to Subtext by @samplereality in #11
• Multiple conversations: opt-in contacts inbox with threads (v2.1.0) by @samplereality in #12

Full Changelog: v0.1.1...v2.1.0