Unified memory entity

Thoughts and insights are now a single vello.memories entity. A memory with no title is a raw capture (equivalent to the old thought — personal-only, cheap, unfiltered). A memory with a title is a curated write-up (equivalent to the old insight). The home page composer is now a single-tab MemoryComposer; the feed shows "Raw" and "Titled" filter tabs instead of "Thoughts" and "Insights". Old /app/thoughts/:id and /app/insights/:id URLs redirect to /app/memories/:id once the backfill migration has been applied. Legacy MCP tools (capture_thought, capture_insight, etc.) remain working; the new default tool is store_memory. Four migration files are included in supabase/migrations/ — apply manually; CI does not run them automatically.

⚠️ After merging, deploy the edge function: supabase functions deploy vello-mcp-v2