. e Add Claude Code configuration for repository

- Created CLAUDE.md with project overview, architecture, and development commands
- Added .claude/settings.local.json to .gitignore to exclude local settings

This provides essential context for future Claude Code instances to work effectively in this repository while keeping local configuration private.

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

Co-Authored-By: Claude <[email protected]>

Author: LarsEckart

.gitignore

@@ -23,4 +23,7 @@ __pycache__/
 **/.jqwik-database
 *.bak
 
-.gitmessage
+.gitmessage
+
+# Claude Code local settings
+.claude/settings.local.json

CLAUDE.md

@@ -0,0 +1,65 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+ApprovalTests.Java is a snapshot-based testing library that simplifies assertions by comparing expected output to approved files. The library supports JUnit 3/4/5 and TestNG, and works with JDK 1.8-25.
+
+## Architecture
+
+This is a multi-module Maven project with the following key modules:
+
+- **approvaltests**: Main library containing core functionality (`Approvals.java`, writers, reporters, namers)
+- **approvaltests-util**: Shared utilities and helper classes
+- **approvaltests-tests**: Integration tests and examples
+- **approvaltests-util-tests**: Tests for utility classes
+- **counter_display**: Sample application
+- **html_locker**: Additional tooling
+
+The core API is in `org.approvaltests.Approvals` class, which provides static methods like `verify()`, `verifyAll()`, `verifyAsJson()`. The library uses a pattern of Writers (generate output), Namers (determine file names), and Reporters (show differences when tests fail).
+
+## Common Commands
+
+### Build and Test
+```bash
+# Full build with all tests
+mvn install
+
+# Build and test (recommended)
+./build_and_test.sh
+
+# Skip tests if some are machine/locale dependent
+mvn install -DskipTests
+
+# Run tests for specific module
+mvn verify -pl approvaltests-tests/
+```
+
+### Development
+```bash
+# Format code
+mvn formatter:format
+
+# Run just the main tests
+./run_tests_without_compile_dependencies.sh
+```
+
+## Key Files and Concepts
+
+- **Approved files**: `*.approved.*` files must be committed to source control and treated as binary in git (add `*.approved.* binary` to `.gitattributes`)
+- **Received files**: Generated during test failures, showing actual output vs approved
+- **Reporters**: Tools that show diffs when tests fail (IntelliJ, Beyond Compare, etc.)
+- **Namers**: Determine approval file naming based on test method/class
+- **Writers**: Generate the actual content to be approved
+
+## Running Single Tests
+
+Individual test methods can be run using standard Maven/IDE approaches:
+```bash
+mvn test -Dtest=ClassName#methodName
+```
+
+## Code Style
+
+The project uses the formatter plugin with configuration in `spun.xml`. Code formatting is enforced via Maven build.