Quorum v0.6.0

What's Changed

• Persist composer drafts across agents by @alchaplinsky in #198
• Fix agent env and per-turn failure surfacing by @alchaplinsky in #199
• refactor(store): extract PTY buffers and settings parsers out of store.ts by @alchaplinsky in #200
• Update settings imports by @alchaplinsky in #201
• Extract helpers from store by @alchaplinsky in #202
• Deduplicate dropAgentEntries and appendToRingBuffer by @alchaplinsky in #203
• Split store.ts into per-domain slices by @alchaplinsky in #204
• Persist new chat agent/model selection by @alchaplinsky in #206
• Defer branch creation to first push; agent-named conventional branches by @alchaplinsky in #205
• Custom agents: reusable provider presets with per-session instruction injection by @alchaplinsky in #207
• feat: open-core extension system (frontend, DB, and backend seams) by @alchaplinsky in #208
• Restructure composer agent picker into flat list + model side panel by @alchaplinsky in #209
• chore: bump version to 0.6.0 by @alchaplinsky in #210

Full Changelog: v0.5.4...v0.6.0