feat(namespace): aggregation reads under the law + epoch 3 (the key-split rebuild) + THE ARMING COMMIT — the capability constant, the law module, and the typed refusals export from the package root; both engines' conformance suites light on this signal

tests/integration/level-field-shadow.test.ts

@@ -141,8 +141,8 @@ describe('level field shadow — user metadata named level is a real field', ()
     expect(Array.isArray(after?.vector) && after!.vector!.length).toBe(384)
   })
 
-  it('this build runs index epoch 2 (the paired level-indexability rebuild)', () => {
-    expect(EXPECTED_INDEX_EPOCH).toBe(2)
+  it('this build runs index epoch 3 (the namespace-law key split rebuild)', () => {
+    expect(EXPECTED_INDEX_EPOCH).toBe(3)
   })
 })