Test that close() waits for the originals precache (closes #93)

The close() test that holds a precache fetch open now runs twice: once
with only the thumbnail fill and once with only the originals fill, so
removing either wait from Precache.close() fails a test.

Model: opus-5-5

TODO.md

@@ -18,6 +18,10 @@ Tag v1.0.0.
 
 # Completed Steps
 
+- 2026-09-23: Tested that `Library.close()` waits for the originals precache
+  (issue 93). The test that holds a precache fetch open while `close()` runs now
+  runs once with only the thumbnail fill and once with only the originals fill,
+  so dropping either wait from `Precache.close()` fails a test.
 - 2026-09-23: Fixed two intermittently failing library tests (issue 90).
   `Library.close()` now returns a promise that resolves once an in-flight
   refresh (including its cache write), the ML data fetch and running precache