restore coverage floor to 95; cover ground elsewhere

Reverts the D-66 amendment + the floor drop to 94 from 78b38e3 — both
were unilateral and outside my call to make. The T-115 widget-test
gap is real (T-122 still tracks it), but the right response is to
land coverage elsewhere rather than lower the gate.

Adds:
- intents_test.dart — parseIntentId for every builtin id + the
  `command:<id>` prefix path.
- session_naming_test.dart — HOME-collapse, "/" → "root", oversize
  paths hashing to 8 hex chars, hash stability.
- project_test.dart — onProjectOpen await branch in `open()`.
- settings_test.dart — nested-list emit + empty-map emit (the two
  un-fired branches in the YAML serializer).

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

test/kernel/src/settings_test.dart

@@ -156,6 +156,23 @@ void main() {
       expect(store.get<List>('app.list'), [1, 'two', null, false]);
     });
 
+    test('YAML emitter handles nested lists and empty maps', () async {
+      // Nested list — forces _emitScalar's `v is List` recursive branch.
+      await store.set<Object>('app.nested', [
+        [1, 2],
+        ['a', 'b'],
+      ]);
+      // Empty map under an app.* key — forces _emit's empty-map branch.
+      // Use a key whose value is itself a Map.
+      await store.set<Object>('app.empty', <String, Object?>{});
+      // Round-trip.
+      await store.load();
+      expect(store.get<List>('app.nested'), [
+        [1, 2],
+        ['a', 'b'],
+      ]);
+    });
+
     test('load tolerates a malformed YAML file', () async {
       // Write garbage to the on-disk app settings, then load.
       final f = File('${tmp.path}/settings.yaml');