Keep binaries until inspected; seeding writes binaries only for inspection

Par2 naming needs the fingerprint inspection stores on a binary, and the
GC deleted seeded binaries (6 h unfingerprinted, 48 h stale) long before
the inspection queue reached them. binaries.awaiting_inspection protects
them for up to 7 days; the GC deletes use partial indexes so they don't
read past waiting rows. Seeding no longer creates binaries for files that
aren't inspected (~85% of a.b.ath), which only churned the table.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

start/env.ts

@@ -105,6 +105,7 @@ export default await Env.create(new URL('../', import.meta.url), {
   ARCHIVE_WALK_CONCURRENCY: Env.schema.number.optional(),
   RELEASE_COMPLETE_INTERVAL_MS: Env.schema.number.optional(),
   FILE_KEYS_FILL_SECONDS: Env.schema.number.optional(),
+  GC_AWAIT_INSPECTION_SECONDS: Env.schema.number.optional(),
   ARCHIVE_WALK_MAX_SEGMENTS: Env.schema.number.optional(),
   DEFERRED_SETTLE_MS: Env.schema.number.optional(),
   DEFERRED_EXPAND_MAX_PARTS: Env.schema.number.optional(),