Ships the first end-to-end mobile-reachable build:
- Rust CLI device add/list/revoke with bearer tokens
- Cloudflare Worker R2 proxy with /v1/health, /v1/index, /v1/messages/:id
- Preact PWA with paste-bundle import, unlock, inbox, message view, compose
- Armored passphrase-encrypted export bundles for cross-device enrollment
- ntfy notification on PWA-side compose
- Cross-language merge contract via shared JSON fixture corpus
- Playwright e2e for the full import to inbox flow

Test totals at this boundary: 80 unit + 35 integration (Rust),
133 unit + 2 e2e (PWA), 30 (Worker). Total 280.

See docs/roadmap.md M4a section for the checklist.