feat(#605): verify video scenes dataset already exists on main

- Add docs/issue-605-verification.md documenting dataset presence
- Add tests/test_prompt_enhancement_video_scenes.py for regression
- 500 record video-scenes-500.jsonl dataset verified on main
- Closes #605

tests/test_prompt_enhancement_video_scenes.py

@@ -0,0 +1,55 @@
+#!/usr/bin/env python3
+"""Verification tests for timmy-config issue #605."""
+
+import json
+import unittest
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parent.parent
+DATA_PATH = ROOT / "training" / "data" / "prompt-enhancement" / "video-scenes-500.jsonl"
+DOC_PATH = ROOT / "docs" / "issue-605-verification.md"
+
+
+def load_records():
+    with DATA_PATH.open("r", encoding="utf-8") as handle:
+        return [json.loads(line) for line in handle if line.strip()]
+
+
+class TestVideoScenesPromptEnhancement(unittest.TestCase):
+    def test_dataset_exists(self):
+        self.assertTrue(DATA_PATH.exists(), f"Missing dataset: {DATA_PATH}")
+
+    def test_dataset_has_500_records(self):
+        self.assertEqual(len(load_records()), 500)
+
+    def test_schema_and_domain(self):
+        for idx, record in enumerate(load_records(), start=1):
+            for key in ("terse", "rich", "domain"):
+                self.assertIn(key, record, f"line {idx}: missing {key}")
+                self.assertIsInstance(record[key], str, f"line {idx}: {key} must be a string")
+                self.assertTrue(record[key].strip(), f"line {idx}: {key} is empty")
+            self.assertEqual(record["domain"], "video scenes", f"line {idx}: wrong domain")
+
+    def test_records_are_unique(self):
+        records = load_records()
+        serialized = [json.dumps(record, sort_keys=True) for record in records]
+        self.assertEqual(len(serialized), len(set(serialized)), "duplicate full records found")
+
+    def test_rich_prompts_include_video_scene_markers(self):
+        for idx, record in enumerate(load_records(), start=1):
+            rich = record["rich"].lower()
+            self.assertIn("lighting", rich, f"line {idx}: rich prompt missing lighting")
+            self.assertIn("composition", rich, f"line {idx}: rich prompt missing composition")
+            self.assertIn("transition", rich, f"line {idx}: rich prompt missing transition")
+
+    def test_verification_doc_exists_and_mentions_evidence(self):
+        self.assertTrue(DOC_PATH.exists(), f"Missing verification doc: {DOC_PATH}")
+        text = DOC_PATH.read_text(encoding="utf-8")
+        self.assertIn("Issue #605 Verification", text)
+        self.assertIn("training/data/prompt-enhancement/video-scenes-500.jsonl", text)
+        self.assertIn("#755", text)
+        self.assertIn("already implemented on `main`", text)
+
+
+if __name__ == "__main__":
+    unittest.main()