fix: unified scraper temp config uses unified format for doc_scraper (#317)

The unified scraper's _scrape_documentation() was creating temp configs
in flat/legacy format (no "sources" key), causing doc_scraper's
ConfigValidator to reject them. Wrap the temp config in unified format
with a "sources" array. Also remove dead code branches and fix a
pre-existing test that didn't clear GITHUB_TOKEN from env.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/test_github_scraper.py

@@ -68,7 +68,12 @@ class TestGitHubScraperInitialization(unittest.TestCase):
             "github_token": "test_token_123",
         }
 
-        with patch("skill_seekers.cli.github_scraper.Github") as mock_github:
+        # Clear GITHUB_TOKEN env var so config token is used (env takes priority)
+        env = {k: v for k, v in os.environ.items() if k != "GITHUB_TOKEN"}
+        with (
+            patch.dict(os.environ, env, clear=True),
+            patch("skill_seekers.cli.github_scraper.Github") as mock_github,
+        ):
             _scraper = self.GitHubScraper(config)
             mock_github.assert_called_once_with("test_token_123")