refactor(tiktok): replace Apify with ScrapeCreators API

Root cause of empty TikTok results: Apify required monthly subscription.
ScrapeCreators is PAYG with 100 free credits and no subscription.

Key fix: ScrapeCreators nests items under aweme_info wrapper
(search_item_list[].aweme_info.{fields}), which the previous
implementation missed, causing all fields to be empty.

Changes:
- Rewrite tiktok.py to use ScrapeCreators REST API
- Add aweme_info unwrapping for correct field extraction
- Add transcript fetching via /video/transcript endpoint
- Add SCRAPECREATORS_API_KEY to env.py config
- Update last30days.py to use env.get_tiktok_token()
- Delete apify_client_wrapper.py (no longer needed)
- Update tests for new date field format (create_time)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/test_tiktok.py

@@ -58,14 +58,10 @@ class TestExtractCoreSubject(unittest.TestCase):
 
 
 class TestParseDate(unittest.TestCase):
-    """Test date parsing from Apify items."""
-
-    def test_iso_date(self):
-        item = {"createTimeISO": "2026-02-28T17:44:35.000Z"}
-        self.assertEqual(tiktok._parse_date(item), "2026-02-28")
+    """Test date parsing from ScrapeCreators items."""
 
     def test_unix_timestamp(self):
-        item = {"createTime": 1756403075}
+        item = {"create_time": 1756403075}
         result = tiktok._parse_date(item)
         self.assertIsNotNone(result)
         self.assertRegex(result, r"\d{4}-\d{2}-\d{2}")
@@ -75,6 +71,19 @@ class TestParseDate(unittest.TestCase):
         self.assertIsNone(tiktok._parse_date(item))
 
 
+class TestCleanWebVTT(unittest.TestCase):
+    """Test WebVTT transcript cleaning."""
+
+    def test_strips_timestamps(self):
+        raw = "WEBVTT\n\n00:00:00.000 --> 00:00:02.000\nHello world\n\n00:00:02.000 --> 00:00:04.000\nGoodbye"
+        result = tiktok._clean_webvtt(raw)
+        self.assertEqual(result, "Hello world Goodbye")
+
+    def test_empty_input(self):
+        self.assertEqual(tiktok._clean_webvtt(""), "")
+        self.assertEqual(tiktok._clean_webvtt(None), "")
+
+
 class TestNormalizeTikTokItems(unittest.TestCase):
     """Test TikTok normalization."""