feat(dashboard): add settings API contract

[powerfulDev-cloud]

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[Lightheartdevs]

Review: REQUEST CHANGES — Hard conflict with PR #364

Blocking: Incompatible /api/settings implementations

PR #363 adds GET /api/settings in main.py with a rich payload (version, services, GPU, model, updates, hostname). PR #364 adds GET /api/settings in routers/runtime.py with a slimmer payload (version, tier, uptime, storage). Different response shapes, different locations, different tests. Cannot both merge.

Recommendation: Merge the richer payload from #363 into the routers/runtime.py location from #364. Both PRs also have near-identical _format_uptime helpers.

Blocking: Verify triggerUpdate exists

Settings.jsx imports triggerUpdate from ../hooks/useVersion, but no changes to that hook are in the diff. If this function doesn't exist on the target branch, the build breaks.

Non-blocking:

• _read_version_state silently returns ("0.0.0", {}) on JSON parse failure — add logger.warning
• socket.gethostname() exposed in API — unnecessary since frontend already has window.location.hostname

🤖 Reviewed with Claude Code