Squash merge PR #115 after resolving changelog and SQLite migration-map conflicts with current dev. Renumbered channel-context PostgreSQL migration to 000075 and bumped PG required schema to 75 plus SQLite schema to 44 so it follows the run timeline migration. Local checks passed: go test ./..., go build ./..., go build -tags sqliteonly ./..., go vet ./..., and pnpm -C ui/web build. PR CI run 26705617311 passed release-versioning, go, and web.