Add remote SSH workspace support: probe/clone/open repos and SSH PTY sessions

[Ziinc]

Motivation

• Enable opening and managing remote repositories over SSH so the app can probe directories, clone repos, and run remote terminal/agent sessions using existing SSH config.

Description

• Add a new core::remote module implementing SSH host parsing, list_configured_hosts, check_readiness, probe_repo, clone_repo, open_repo, build_ssh_shell_command, quoting/validation helpers, and corresponding data types (SshHost, RemoteReadiness, RemoteRepoProbe, RemoteRepository).
• Expose remote operations through the native dispatcher (treq-napi::dispatch) and a new Tauri command module commands::remote, and register these commands in the app runtime.
• Wire remote SSH into PTY sessions by adding an optional remote_host parameter to pty_create_session, building an ssh shell command via build_ssh_shell_command, and passing shell_args into PtyManager::create_session so remote sessions spawn the appropriate ssh invocation.
• Surface APIs and types to the frontend by adding new entries to src/lib/api.ts, src/lib/api-types.ts, and src/lib/api-extra.ts, plus UI changes including a new onboarding "Open via SSH" button, a File menu item, a menu event handler, and a dashboard flow to probe/clone/open remote repos and remember recent hosts.
• Add documentation web/docs/how-to/remote-ssh-workspaces.md describing usage and caveats.

Testing

• Ran Rust unit tests for the new remote module via cargo test and the module-level tests passed.
• Ran the Tauri command unit test and the new frontend integration tests using vitest and they passed locally.
  [Codex Task](

[github-actions]

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📊 Lighthouse report: https://github.com/Ziinc/treq/actions/runs/29472882663/artifacts/8365435794