GRE-226: activate and roll back qualified releases

[HeadCase]

Summary

• install immutable, checksummed appliance compatibility sets with transactional active and previous links
• validate bounded live health, assets, MediaMTX publication, runtime paths, SDK mapping, and independent service recovery
• support explicit GRE-225 adoption, automatic restoration, installed-command upgrades, read-only status, and manual rollback
• preserve AllSky ownership and expose operator-readable release evidence

Verification

• cargo fmt --all -- --check
• cargo clippy --workspace --all-targets --all-features -- -D warnings
• cargo test --workspace --all-targets --all-features
• cargo deny check
• cargo machete
• npm run typecheck:browser
• npm test
• deployment shell suites and staged systemd-analyze verify
• independent Standards and Spec reviews: no remaining findings

Live appliance qualification

• real Raspberry Pi, ASI662MC, ZWO SDK 1.41, hardware H.264, MediaMTX v1.19.3, and systemd supervision
• failed candidate automatically restored the previous qualified set with no pending journals
• installed-command upgrade and explicit manual rollback passed
• final active release gre-226-407bf2c-d; previous gre-226-432e805-b
• desktop and mobile Mac Chromium over wg0: Live, advancing 1920x1080 video, WHEP 201, API 200, no overflow, console errors, or failed requests
• AllSky service definition remained unchanged

Detailed evidence: docs/verification/gre-226-qualified-releases.md