chore(#2089): gitignore compiled imperative-hook-bus adapter + fix Context7 typo

- Add /gsd-core/bin/lib/host-integration-adapters/imperative-hook-bus.cjs to
  .gitignore (tsc-emitted build artifact per ADR-457 convention; matches the
  sibling adapter entries at .gitignore:70-89). The subagent authored the
  .cts source but missed this entry, leaving the compiled output untracked.
- Fix cosmetic 'Context3' -> 'Context7' typo in test section header comment.

.gitignore

@@ -69,6 +69,7 @@ build/
 /tsconfig.build.tsbuildinfo
 /gsd-core/bin/lib/host-integration.cjs
 /gsd-core/bin/lib/host-integration-sdk.cjs
+/gsd-core/bin/lib/host-integration-adapters/imperative-hook-bus.cjs
 /gsd-core/bin/lib/handshake-serialized.cjs
 /gsd-core/bin/lib/install-effort-resolver.cjs
 /gsd-core/bin/lib/install-engine.cjs

tests/cursor-imperative-reference.test.cjs

@@ -66,7 +66,7 @@ test('cursor descriptor declares all 8 axes + 6 dispatch sub-axes (no undocument
   assert.equal(d.backgroundDispatch, true);
 });
 
-// -- AC4b: the Context3-verified dispatch UPGRADE (named/background nested) ---
+// -- AC4b: the Context7-verified dispatch UPGRADE (named/background nested) ---
 
 test('cursor descriptor declares background dispatch true/true + nested + maxDepth 2', () => {
   assert.equal(CUR_AXES.dispatch.background, true);