Playground Maintenance Sweep — 9 Fixes, 0 Broken Links

Another full audit of the Playground, and another full cleanup. This pass fixed dead navigation, broken styles, a crash-looping service, and closed a small information leak. The whole site now passes a 31-page sweep with zero broken references (down from 27).

What changed

• Navigation repaired — the Labs & Misfits pages (Constellation, Jarvis Flow, MIDI Creator) had links pointing to files that moved months ago, plus two menu items for pages that no longer exist. All fixed; dead entries removed.
• Styles restored — the Gallery, SNES Arcade, and Space Invaders pages were loading their navbar CSS from the wrong path, and two Labs pages were missing their entire design system. Everything loads again.
• Crash-loop stopped — a duplicate MIDI API service had been restarting every 10 seconds since boot (140+ attempts). The real service runs fine; the duplicate is retired.
• Security hardening — three API source files and the package manifests were publicly downloadable from the site root. They're now blocked (403), app code unaffected.
• Sitemap rebuilt — it was stuck in May and missing ~15 apps. All 30 current URLs are now listed.
• Cleanup — a stale duplicate of the 360° Video app (May 2026) removed from Labs, and six obsolete service definitions retired.

Nothing new to play with this time — just the site working the way it should. All changes verified end-to-end and committed to the repo.