row284: cover absent supporting prefix directly (unrun)

agents/della/work/queue-284/BUILD.md

@@ -174,3 +174,23 @@ query.test.mjs:369: `const own = await get(src(ref), { universe: 'harbor', path,
 query.test.mjs:370: `assert.equal(own.scope, 'playground');`
 
 No result/null assertion changed; scope arguments carry the explicit opt-in.
+
+## Dewey dewey-0941 static review — round2
+
+Static scope fc05bcbc3..47db04eba CLEAN; not a final verdict or test evidence.
+M1-M9 accepted as the final set. Optional M10 not added to this gate.
+N2 taken: keep the existing canon-path supporting-scope mismatch assertion,
+and ADD get(Book One/Support/Notes/Helper.md,scope:supporting) -> null under
+the default mapping with no supporting prefix. The supporting-positive test
+already returns this same path under withSupporting, so the added probe
+pins the missing-prefix case directly. No assertion removed or weakened;
+mos1330's separate migration commit and its retained assertions unchanged.
+
+N1 proposed DEFERRED/follow-up for Sage: retain each tree oid in reader/index
+entries so get can return blob without cat-file/whole ls-tree -r -l per page.
+Current get's result is pinned correctly, but per-page cost grows with the
+library. No performance measurement yet. This optimization needs reader/index
+ownership and separate acceptance/performance evidence; do not silently expand
+284's manifest or change its served-snapshot contract for it.
+
+No Node, tests, mutants or syntax checks run in this round; hold still applies.

packages/library/tests/query.test.mjs

@@ -402,6 +402,7 @@ test('C2-05c an absent supporting prefix returns nothing without refusal', async
   assert.deepEqual((await find(s, { universe: 'harbor', query: '', scope: 'supporting' })).results, []);
   assert.deepEqual((await search(s, { universe: 'harbor', text: 'Scope fixture', scope: 'supporting' })).results, []);
   assert.equal(await get(s, { universe: 'harbor', path: 'Book One/Characters/Canon.md', scope: 'supporting' }), null);
+  assert.equal(await get(s, { universe: 'harbor', path: 'Book One/Support/Notes/Helper.md', scope: 'supporting' }), null);
 });
 
 test('C2-05c each get blob equals its served tree object, even after source HEAD advances', async t => {