Migration now imports all archive files (oldest first) in addition to the
live .msgs file, with deduplication. Archives endpoint and message history
now query SQLite by date instead of reading .msgs files.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Reads the existing .msgs JSONL file and imports channel messages and DMs
into the v2 SQLite database. Runs automatically when device connects and
DB is empty. Handles sender parsing, pubkey resolution, and FK constraints.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>