NOT READY: Add standalone CLI and desktop distribution

[Shugar]

Adds a self-contained moi installation and a thin Tauri desktop shell without forking product behavior from main. The desktop app provisions the same runtime, installs main's background service when available, and falls back to an app-owned server; standalone users keep main's moi update and release/tag semantics.

CLI installer ─┐
Desktop shell ─┴─ shared ~/.moi runtime ── main service / update / tags

Desktop launches the existing React client unchanged. Its small pre-server boot/error surface compiles from the main Tailwind theme and canonical pixel icon, with Try again and Copy diagnostics recovery actions.

Review focus:

• Atomic runtime download, checksum verification, extraction, and symlink locking.
• Background service installation and app-owned fallback behavior on macOS and Linux.
• Stable release matrices, checksums, and GitHub release assembly.

Verification:

• Explicitly rebased against freshly fetched origin/main at 875f507 — already up to date.
• bun test — 937 passed, 4 skipped, 0 failed.
• bun run lint, bun run format:check, and bun run typecheck:client.
• Rust formatting and clippy with warnings denied.
• Desktop Rust tests — 5 passed, 0 failed.
• Production standalone tarball/checksum smoke and macOS DMG build.
• Compiled boot UI checked at normal and 480 × 480 window sizes.

Docs cover standalone installation, updates, services, uninstall, and desktop lifecycle.