Data and migrations

Location: the OS app-data folder for the legacy identifier it.nodex.desktop (kept so existing archives open). Before the first restore the database is nodex.sqlite3 in that folder; afterwards active-profile.json selects profiles/<UUID>/. Never move the database alone.
Migrations: src-tauri/migrations/NNN_name.sql, applied once, in a transaction. A migration must never destroy data without a recovery path. Bump the schema only with a migration and update backup validation.
Keys: UUIDs everywhere; titles are data, never keys.
Revisions: documents carry a revision; a save based on an old revision is refused ("changed elsewhere").
Backups (.nodex): ZIP with a v1 manifest and a SHA-256 per file, a SQLite snapshot, managed attachments and imported sources. Restores verify everything, write a safety copy first and switch to a new profile generation. Older schemas restore and migrate in the copy.
Debug profiles: debug builds honour NODEX_DEV_DATA_DIR and NODEX_DEV_DOCUMENTS_DIR (absolute, new folders). Never point them at personal data.
Outside the archive: interface and wiki preferences (JSON next to the profiles), the sharing session (sync-account.json), AI weights and runtime. None enter Git.

Details: docs/DECISIONS.md, docs/STATUS.md, src-tauri/src/backup.rs.

Using Chronexus

For developers