feat(testing): add end-to-end HTML scraping and parsing tests with typed parsers

- Add smart httpx MockTransport routing based on endpoint paths
- Render HTML fixtures via Jinja templates populated from JSON data
- Introduce explicit, typed HTML parsers for semantic and table-based content
- Add end-to-end tests covering scraper → content → parser → Pydantic models
- Enforce explicit output contracts and avoid default dict-based parsing

tests/mocks/simple.json

@@ -0,0 +1,7 @@
+{
+  "title": "Test Page",
+  "description": "Simple test page",
+  "content": "Hello World",
+  "link_url": "https://example.com",
+  "link_text": "Link"
+}