Bump version to 1.2.0 and update documentation

Update README.md:
- Reflect current architecture (housekeeping, infrastructure, tools)
- Document all API endpoints
- Add environment variables reference
- Update test instructions

Update CHANGELOG.md:
- Document housekeeping API addition
- Document web scraper removal
- Document test coverage improvements

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "core-api"
-version = "1.1.2"
+version = "1.2.0"
 description = "Core Code API - Infrastructure management and tools API"
 readme = "README.md"
 requires-python = ">=3.12"