Add LiveView desktop fleet app with verified macOS packaging

[jhgaylor]

Manasprites now has a native macOS desktop app for managing coding agents on Sprites: create or connect agents, run independent conversations, answer approvals, interrupt work, and inspect files and Git changes. The README leads with the desktop workflow and real native screenshots; the CLI remains available in a secondary guide.

The laptop backend is Elixir + Phoenix LiveView, with OTP supervising connections/jobs and SQLite/Ecto persisting local state. Tauri + ElixirKit embeds the runtime and owns the native window lifecycle. Credentials stay in an encrypted local vault; provisioning sends only selected credentials to the chosen Sprite. Existing CLI and service API contracts are retained.

Live qualification exposed Codex's automatic-review default resolving requests before the service's ask policy saw them. Service 0.1.1 now routes those requests to the ACP peer, and the desktop pins that published release. The exact archive passed fresh installation, real allow/deny workflows, and upgrade/continuation checks before and after publication.

Validation:

• 24 desktop tests use actual local service processes, ACP ScriptedAgents and Python/Git subprocesses; both Linux release builds pass 31 service and all 48 installer/CLI tests.
• Native WebKit walkthrough covers credential settings, attachment, simultaneous approval waits, continuation, interruption, discovery/creation, file previews, staged/unstaged Git diffs, local removal and restart.
• The app requires macOS 15; packaging rejects mismatches between the app minimum and native binary deployment targets. Extracted ZIP tests verify native launch with system-only PATH, SQLite persistence/exclusive ownership, and BEAM/listener cleanup after normal exit and SIGKILL. The hosted Apple Silicon archive also passed these checks after downloading to the development Mac.
• Live checks cover public/private creation and authentication, overlapping work on two Codex agents, exact file/Git results, cold wake, real approval answers, and a follow-up recalling pre-upgrade context without reading files. All disposable Sprites were removed after ownership checks; private local state and credentials were deleted.
• Three README screenshots contain only synthetic demo data. A notarized-release packaging gate refuses the actual ad-hoc app before archiving.

Remaining gates are recorded in docs/desktop-acceptance.md: final hosted results for the latest source, funded Claude qualification, and Developer ID signing/notarization and desktop publication. Apple credentials are currently unavailable. This PR does not claim a signed desktop release.