[ael-dev3]

A cold location currently waits for a full Home rebuild when the shared public copy is 60–600 seconds old, even though that age is inside the existing stale period. Serve that validated copy with its original timestamp and current time bounds, then start one coalesced background refresh. A transient claim prevents late joined requests from duplicating a fast failed refresh, and an expiry check keeps an aged-out seed from being served.

Browser dependency acquisition also exhausted the CI job after Azure’s Ubuntu mirror took 10m11s to fetch 25.9 MB. A guarded native Rust command selects Canonical’s HTTPS archive in supported Ubuntu APT configurations before the existing Playwright dependency installation. It preserves signing settings, security entries, package suites, dependencies and fonts. The test sequence, assertions, workers, triggers and job caps remain unchanged.

Validation:

• cargo xtask check: 781 native tests, native/Wasm Clippy, formatting and licenses pass.
• cargo xtask module-check: 17 tests and release Wasm pass; Node boundary tests: 24 pass.
• Production and static builds pass. Focused Home/first-paint/range tests: 39 pass; static selection: 20 pass, 19 expected skips. All completed without retries.
• Fourteen added native tests cover delayed source reads, budgets, expiration, failed refreshes, late joiners, mirror formats and configuration safety.

Cold-load performance and complete normal CI still require validation on this source.