feat(code): complete worker initialization wizard

[danii1]

Summary

• make devintern worker init create and safely configure the workspace for the current repository
• add login and workspace-scoped relay onboarding, including tracker and GitHub repository registration
• generate user-level systemd or launchd service definitions for persistent workers
• start the dashboard by default, support --no-ui, and keep workers alive if dashboard startup fails
• route workspace state and single-repository events consistently, including tracker relay events without GitHub credentials
• update worker, workspace, relay, dashboard, and changelog documentation

This completes the wizard/workspace slice of the unattended worker roadmap. Scheduling, quiet hours, dashboard retry controls, GitHub App installation guidance, configuration reload, and the later concurrency/remote execution work remain separate follow-ups.

Behavior

The recommended setup is now:

1. Run devintern worker init in a repository.
2. Sign in and connect the relay when prompted.
3. Install the generated background service.
4. Confirm the worker through http://localhost:4400.

Existing workspaces are not silently repointed to a different repository. Additional repositories must be imported explicitly.

Validation

• root format, lint, and typecheck hooks passed
• full monorepo pre-push test and typecheck pipeline passed
• @getdevintern/code: 893 tests passed, 0 failed
• production @getdevintern/code bundle built successfully with dashboard UI
• git diff --check passed