feat: integrate bilibili-extractor into obsidian-kb

- Add extractors layer with BilibiliExtractor (Playwright stealth mode)
- Add outputs layer with ObsidianWriter and GitSync
- Implement subtitle/no-subtitle graceful degradation
- Update config with output and bilibili extraction settings
- Complete integration pipeline: extract → process → output → sync
- Add comprehensive tests (100% pass rate)
- Update documentation (SKILL.md, README.md, requirements.txt)

skills/obsidian-kb/src/config.py

@@ -51,10 +51,20 @@ class Config:
             'max_chunk_duration_seconds': 1800,  # 30 minutes
             'long_video_threshold': 1800,  # 30 minutes
         },
+        'output': {
+            'organize_by': 'author',           # author | date | topic
+            'filename_format': '{date}_{title}.md',
+            'auto_tags': True,
+            'default_tags': ['video', 'bilibili'],
+        },
         'sources': {
             'bilibili': {
                 'enabled': True,
                 'cookie': None,
+                'extraction': {
+                    'headless': True,
+                    'timeout': 30,
+                },
             },
             'youtube': {
                 'enabled': False,
@@ -254,6 +264,38 @@ class Config:
         """Get Kimi API key (alias for ai.api_key)."""
         return self.get('ai.api_key') or ''
     
+    # Output configuration
+    @property
+    def organize_by(self) -> str:
+        """Get output organize_by strategy."""
+        return self.get('output.organize_by', 'author')
+    
+    @property
+    def filename_format(self) -> str:
+        """Get output filename format."""
+        return self.get('output.filename_format', '{date}_{title}.md')
+    
+    @property
+    def auto_tags(self) -> bool:
+        """Get auto_tags setting."""
+        return self.get('output.auto_tags', True)
+    
+    @property
+    def default_tags(self) -> list:
+        """Get default tags list."""
+        return self.get('output.default_tags', ['video', 'bilibili'])
+    
+    # Bilibili extraction configuration
+    @property
+    def bilibili_headless(self) -> bool:
+        """Get bilibili extraction headless mode."""
+        return self.get('sources.bilibili.extraction.headless', True)
+    
+    @property
+    def bilibili_timeout(self) -> int:
+        """Get bilibili extraction timeout in seconds."""
+        return self.get('sources.bilibili.extraction.timeout', 30)
+    
     def ensure_dirs(self) -> None:
         """Ensure required directories exist."""
         self.vault_path.mkdir(parents=True, exist_ok=True)