feat(desktop): implement optional Linux native integration #2110

Goal

Provide the native Desktop boundaries required on Ubuntu 24.04 LTS x86_64 with GNOME while reusing the shared UI and public Server contracts.

Parent: #1428. Optional follow-up to first-wave delivery #2099. Work item: F1-08a.

PR breakdown

• PR 08-E — Linux personal service integration (optional workstream). Adapt the shared structured Ops/installer boundary to systemd --user and the qualified Linux runtime resources. Preserve existing controller ownership, explicit-stop semantics, and user-session lifetime; test actual service registration/start/stop/removal and recovery. Document login/logout behavior without silently enabling system-wide persistence or requiring root.

• PR 08-A — Linux credentials and packaged application boundary. Implement native persistent credential storage, explicit session-only fallback choice, packaged navigation/IPC, and required platform configuration. Cover unavailable/locked credential storage without plaintext fallback.

• PR 08-B — Constrained diagnostics and desktop integration. Implement trusted registered diagnostic launchers and necessary Linux desktop behavior, preserving deadlines, bounded output, cancellation, and descendant cleanup.

Dependencies and coordination

• This is owner-driven optional work: name a contributor with access to the target Linux sessions before scheduling acceptance. Tracking: ship Desktop with local Server setup on Windows and macOS #2099 and required Windows/macOS implementation/publication do not wait for this issue.

• Consume feat(installer): bootstrap a managed local PowerContext runtime #2115/feat(ops): expose structured personal Server lifecycle operations #2116 shared resource, ownership, plan, and operation contracts for Linux local setup; avoid Linux branches that block or redefine the required Windows/macOS contracts.

• Coordinate with build(desktop): package and qualify the optional Ubuntu Desktop preview #2111 on distro/system dependencies, package identity, and Wayland/X11 qualification. Native work and packaging scaffolding can proceed in parallel.

• Reuse shared transport/context boundaries from feat(desktop): integrate Server discovery and operation compatibility #2101 and review applicable Unix process-management work from feat(desktop): add macOS native preview support #2056 without assuming macOS acceptance qualifies Linux.

• Coordinate diagnostic outputs with feat(desktop): visualize health and processing observations #2105 and shared UI expectations with feat(desktop): establish the shared application layout and navigation #2102; avoid Linux-specific business semantics.

Acceptance criteria

• A named Linux owner records real systemd --user behavior for local provisioning/management, including unavailable user service manager, login/session lifecycle, explicit stop, damaged runtime, and preserved data. Reuse feat(ops): expose structured personal Server lifecycle operations #2116's semantics; GUI exit is not a Server stop command.

• Missing Linux adapters/builds cannot fail required Windows/macOS release jobs or advertise Linux support prematurely. build(desktop): package and qualify the optional Ubuntu Desktop preview #2111 qualifies the complete Linux package before public support is claimed.

• Packaged navigation and typed IPC work on Linux through the intended local origin without broadening remote renderer/network authority.

• Native credential storage persists and deletes only the application's own credentials. Unavailable/locked storage is actionable; session-only storage requires explicit choice, with no plaintext downgrade.

• Registered diagnostics verify trusted executable identity and accept only supported fixed operations. No arbitrary renderer command or PATH-first executable selection is added.

• Deadline, output limits, cancellation, and descendant cleanup hold under actual Linux process execution. Absence/failure of local tools does not disable remote operations.

• Native behavior works in the declared GNOME session environments; share actual results and system dependencies with build(desktop): package and qualify the optional Ubuntu Desktop preview #2111.

• Focused regression checks preserve transport/credential boundaries; mocks or direct hook invocation are distinguished from real Linux native execution.

Delivery priority

Windows 11 x64 and macOS Apple Silicon/Intel are required for #2099. Linux #2110 and #2111 are optional, owner-driven work under #1428; missing Linux implementation, packaging, or qualification does not block this issue's first-wave acceptance or the Windows/macOS release. Any advertised Linux support requires its own actual qualification.

Non-goals

No Debian publication in this issue, arbitrary shell execution, universal Linux distribution support, system-wide/root service installation, or independent Linux business rules. Shared Installer/Ops remain owned by #2115/#2116.

References and delivery rules

• Product scope and PR breakdown; static UI prototype. The prototype uses sample data, not production state logic.
• RFC docs(rfc): propose Tauri desktop control center #1455 and the Desktop delivery plan.
• Keep focused PRs independently reviewable and intermediate merges usable. An internal adapter may land before its page; do not expose incomplete features as operational. Close this issue only after its complete outcome is verified.
• Preserve the reviewed native transport, credential, public API, and context boundaries. Record actual backend/platform execution separately from mocks and CI-only fixtures.