Serve the Home Assistant OS link on port 80, with 8123 as its alternate

[eschultz]

Summary

Home Assistant 2026.8 (2026-08-05) serves new Home Assistant OS installs on port 80 instead of 8123. Older installs keep 8123, and nothing on 8123 redirects. Every HAOS VM HexOS installs runs current Core, so it comes up on port 80, and the VM card's Launch link to http://{ip}:8123 opens a refused connection (reported on r/hexos on 2026-10-10).

Changes:

• home-assistant-os.json:
  • postInstallUrl is http://{ip}, and the new postInstallAltPorts: [8123] lists the port older installs serve. eshtek/hexos-platform#2105 probes both and links to the one that answers.
  • readiness.port is 80, so the mDNS probe can confirm a fresh install. Before this, it only got through on the guest agent's three-strike fallback.
  • The onboarding hook's guestPort is 80, with 8123 as its alternate.
• Vendored schemas: re-vendored with bun run sync-schema from the hexos-platform#2105 branch (based on staging@a8e2eb881). Adds postInstallAltPorts. It also brings staging's gpuSharing capability (eshtek/hexos-platform#2104), which nothing here uses.
• README: the blueprint example and the hook example show the new ports and the field.

What changes for users once this syncs:

• New HAOS installs link to port 80.
• On a platform without hexos-platform#2105, the field is stripped and each existing HAOS VM's link is rebuilt from the template at its next HexOS start (after the box's backend restarts, since it caches the guest config). That fixes VMs installed since August. An install from before 2026.8 that still serves 8123 would get a port-80 link until the box runs hexos-platform#2105, which moves it back.
• With hexos-platform#2105, running VMs are corrected in place to whichever port answers.

Promoting staging to prod also carries #24 (Plex on virtiofs), whose platform half, eshtek/hexos-platform#2043, reached prod in the 2026-10-10 release.

Test plan

• bun run validate: 29 blueprints and 32 apps, 0 errors. The one HAOS warning (id differs from the filename) was already there.
• bun run test-hooks: 81 pass.
• bun run typecheck: the same 5 errors in the vendored vm-surfaces.ts as on staging, none from this PR.
• The HAOS document parses with the platform schema from hexos-platform#2105: guest config keeps postInstallAltPorts, and the hook resolves to port 80 with 8123 as its alternate.
• After merge: sync to staging, install HAOS once, and confirm Launch opens the UI on port 80.