Exclude cold module loads from guest deadlines

docs/wasm-runtime-architecture.md

@@ -131,6 +131,10 @@ available. If an artifact is cold or stale, dispatch compiles it on demand via
 Workers identify cached unit artifacts by nanosecond mtime, ctime, and size.
 Whole-second mtime alone is insufficient because a dependency-triggered rebuild
 can replace a wasm artifact within the same second as its prior build.
+Cold module compilation and deserialization are host work, so `load_unit()`
+refreshes the epoch deadline before its first guest call. Otherwise a component
+whose compilation outlasted the guest CPU budget would immediately trap in the
+following allocator/relocation call even though no guest loop consumed it.
 
 ---
 
@@ -330,9 +334,11 @@ header free-functions are `inline`. The wasm backend exposes only declarations
   `scripts/test_dependency_invalidation.sh`. The latter changes a transitive
   `#load`, then replaces a warmed worker artifact while preserving its
   whole-second mtime to prove both compiler and worker caches invalidate it.
+  `scripts/test_cold_component_deadline.sh` separately compiles a deliberately
+  cold component that exceeds the development epoch window and proves the
+  parent request still renders it.
 
 - **WebSocket end-to-end**: a headless client performs a raw WS handshake to
   `:HTTP_PORT` with path `/site/tests/websockets.ws.uce` (self-resolving
   `SCRIPT_FILENAME`) and asserts the `hello-ack` frame — exercising the full
   broker → worker → broker → client chain across process boundaries.
-