* fix(test): load compiled-subprocess declarations at collection
The first load of a compiled-subprocess declaration in a Vitest invocation
prepares the whole compiled worker generation (tens of seconds warm, minutes
cold). 387 test files first reached a declaration through an await import()
inside a test body or hook, so their first test or hook absorbed that
preparation and could time out.
Move those loads to collection at their owner: static subject imports,
static imports in the shared helpers that owned the lazy load, and a named
side-effect preload (src/test-utils/prepare-compiled-subprocesses.ts) for
suites that re-import their subject per test or whose first load happens in
production code they call. plugin-test-runtime keeps the host-capability
fixture lazy so its other consumers do not start loading that graph.
Document the rule in docs/help/testing/writing-tests.md.
335 of the 387 files now load their first declaration before collection
ends; 52 remain (48 extension tests needing an SDK preload, one package
test, three files over the line cap).
* fix(test): retain npm install fixture reuse
Preserve the existing failedSpawn reuse after merging main so the collection-time preload stays within the line-cap ratchet. Assertions and import ordering are unchanged.
* fix(test): keep memory-core facade cold-import assertion meaningful
The static subject import ran before beforeEach reset the loader mock, so the cold-import assertion passed vacuously. Restore the in-test subject imports after mock setup and preload the compiled-subprocess declaration during collection instead.
