[ael-dev3]

A cold or expired regional Home cache currently blocks on the complete upstream feed build. Main CI measured a 2,776 ms cold-load LCP median against the unchanged 1,500 ms budget; its passing retry correctly failed the strict flaky gate.

Reuse a validated public 24-hour Home snapshot from D1 when it is less than 60 seconds old. Preserve its original age, filter current time bounds, and keep normal background refreshes and private feeds unchanged. Optional saves run in the background and prevent older concurrent builds from replacing newer copies.

Validation:

• 605 Rust tests, formatting, native/WebAssembly/static Clippy and license checks passed.
• Real SQLite ordering, failure and future-row recovery regression passed.
• Optimized Worker/browser and static builds passed.
• Three actual local Worker/D1 cases, 17 affected browser cases and all 25 tooling tests passed; static fixtures passed 17 with 12 declared skips.

The first global build still uses upstream assembly. Production LCP and the full production suite remain release gates. This change preserves timing budgets, cold contexts, sample counts, workflow triggers, retries and strict flaky detection.