feat: add .serena path instructions and CLAUDE.md

CLAUDE.md

@@ -0,0 +1,45 @@
+# CLAUDE.md
+
+## Repository Purpose
+
+Centralized CodeRabbit AI code review configuration. Contains a single `coderabbit.yaml`
+referenced by other repositories via `remote_config`. No source code — configuration only.
+
+## Validation Commands
+
+```bash
+# Run all checks (YAML lint, schema validation, editorconfig)
+pre-commit run --all-files
+
+# Individual checks
+yamllint --strict .                # YAML linting
+check-jsonschema --schemafile \
+  'https://storage.googleapis.com/coderabbit_public_assets/schema.v2.json' \
+  coderabbit.yaml                  # Schema validation
+```
+
+CI runs `pre-commit/action@v3.0.1` on push/PR to `main`.
+
+## Architecture
+
+```
+coderabbit.yaml          # Main config — schema.v2.json validated
+.yamllint.yaml           # yamllint rules (120 char lines, strict)
+.pre-commit-config.yaml  # Pre-commit hooks: check-yaml, yamllint, schema, editorconfig
+.editorconfig            # 2-space indent, UTF-8, LF line endings
+.github/workflows/       # CI validation via pre-commit
+```
+
+Other repos consume this config by adding to their `.coderabbit.yaml`:
+```yaml
+remote_config:
+  url: "https://raw.githubusercontent.com/ivuorinen/coderabbit/refs/heads/main/coderabbit.yaml"
+```
+
+## Conventions
+
+- YAML files start with `---` document marker
+- 2-space indentation, UTF-8, LF line endings
+- Max line length: 120 characters
+- Schema reference: `# yaml-language-server: $schema=https://storage.googleapis.com/coderabbit_public_assets/schema.v2.json`
+- Always validate against the official CodeRabbit schema before committing