feat(simulator): deterministic synthetic fixture catalog

Per docs/superpowers/plans/2026-06-04-experience-simulator.md Task 3.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tests/test_fixtures.py

@@ -0,0 +1,40 @@
+from hef.catalog import validate_catalog
+from hef.selection import CONTENT_MODES
+from simulator.fixtures import generate_fixture_catalog
+
+
+def test_fixture_catalog_is_valid():
+    records = generate_fixture_catalog()
+    validate_catalog(records)  # raises on any invalid record or duplicate id
+
+
+def test_fixture_catalog_spans_the_coordinate_space():
+    records = generate_fixture_catalog()
+    coords = {(r.left, r.right, r.dark, r.light) for r in records}
+    # all 625 cells of the 5x5 brain x 5x5 mood space are present
+    assert len(coords) == 625
+
+
+def test_fixture_catalog_has_every_content_mode():
+    records = generate_fixture_catalog()
+    present = {r.mode for r in records}
+    assert CONTENT_MODES <= present
+
+
+def test_fixture_catalog_mixes_review_statuses():
+    records = generate_fixture_catalog()
+    statuses = {r.review_status for r in records}
+    assert statuses == {"proposed", "approved"}
+
+
+def test_fixture_catalog_references_no_real_media():
+    records = generate_fixture_catalog()
+    assert all(r.file_path == "" for r in records)
+
+
+def test_fixture_catalog_is_deterministic():
+    a = generate_fixture_catalog(seed=42)
+    b = generate_fixture_catalog(seed=42)
+    assert [r.id for r in a] == [r.id for r in b]
+    assert [r.mode for r in a] == [r.mode for r in b]
+    assert [r.review_status for r in a] == [r.review_status for r in b]