fix(cache): increase stale-while-revalidate TTL to 1 hour (#1136)

* fix(cache): increase stale-while-revalidate TTL to 1 hour

- STALE_TTL_PERIOD default: 30s → 3600s (1h)
  Keeps loader cache entries in LRU as stale fallback during origin
  slowdowns. Previously items were evicted after 90s total (60s fresh
  + 30s stale), leaving cache misses exposed to full origin latency.

- DECO_PAGE_CACHE_CONTROL stale-while-revalidate: 30s → 3600s (1h)
  CDN can serve stale HTML for up to 1h while revalidating in background,
  reducing origin pressure during high latency spikes.

Both values remain overridable via env vars.

* fix(cache): add stale-if-error=86400 to page cache control

Aligns middleware PAGE_CACHE_CONTROL with the existing pattern in
routes/render.tsx. Ensures CDN serves stale HTML on origin errors
(5xx, timeout) for up to 24h, regardless of CDN implementation.

* fix(cache): prevent NaN ttl when expires header is missing

Date.parse('') returns NaN, causing ttl = NaN + STALE_TTL_PERIOD = NaN.
lru-cache disables TTL entirely when NaN is passed, making items
persist indefinitely. Fall back to STALE_TTL_PERIOD when expires is absent.

* Update cache control settings in middleware

* Change default STALE_TTL_PERIOD from 1 hour to 30 seconds

* Update runtime/middleware.ts

Co-authored-by: cubic-dev-ai[bot] <191113872+cubic-dev-ai[bot]@users.noreply.github.com>

* Update middleware.ts

* Update lrucache.ts

---------

Co-authored-by: cubic-dev-ai[bot] <191113872+cubic-dev-ai[bot]@users.noreply.github.com>

Author: igoramf

runtime/middleware.ts

@@ -108,7 +108,7 @@ const DEBUG_COOKIE = "deco_debug";
 const DEBUG_ENABLED = "enabled";
 const PAGE_CACHE_ENABLED = Deno.env.get("DECO_PAGE_CACHE_ENABLED") === "true";
 const PAGE_CACHE_CONTROL = Deno.env.get("DECO_PAGE_CACHE_CONTROL") ??
-  "public, max-age=90, s-maxage=90, stale-while-revalidate=30";
+  "public, max-age=90, s-maxage=90, stale-while-revalidate=3600, stale-if-error=86400";
 
 export const DEBUG_QS = "__d";
 const addHours = (date: Date, h: number) => {