feat(08-01): create crawler data models and test scaffolding

- Add Pydantic models: AnswerData, ArticleData, ContentMetadata, AuthorInfo, CrawlResult
- Create test fixtures in conftest.py with mock browser and sample API responses
- Set up crawler module with __init__.py exports

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

kb_workflow/crawler/__init__.py

@@ -0,0 +1,20 @@
+"""Zhihu Crawler Module
+
+Provides content crawling capabilities for Zhihu using Playwright API interception.
+"""
+
+from .models import (
+    AuthorInfo,
+    ContentMetadata,
+    AnswerData,
+    ArticleData,
+    CrawlResult,
+)
+
+__all__ = [
+    "AuthorInfo",
+    "ContentMetadata",
+    "AnswerData",
+    "ArticleData",
+    "CrawlResult",
+]