Update documentation for API, configuration, and model

API.md:
- Add export formats (JSON, XML, EGF, FFG, CSV)
- Document /explain endpoint for pairing analysis
- Add PUT /standings for freezing
- Improve parameter documentation
- Fix typos (regitration -> registration, #tip -> #tid)

configuration.md:
- Add property loading hierarchy
- Document SSL/TLS configuration
- Add OAuth provider configuration
- Add ratings.path property
- Include example configurations

model.md:
- Complete entity diagram with Team, external IDs
- Document all tournament types (PAIRGO, RENGO, TEAM)
- Add TimeSystem types and parameters
- Document all pairing parameters
- List all 39 tiebreak criteria
- Add external database (AGA, EGF, FFG) documentation

.gitignore

@@ -1,3 +1,4 @@
+.claude
 target
 /docker/data
 /.idea