feat: add comprehensive README documentation and clean up configuration

## Documentation Enhancements
- Create comprehensive README with installation, configuration, and usage examples
- Add simple, advanced, and provider-specific configuration examples
- Document all features: incremental sync, wildcard patterns, keyword filtering, attachment support
- Include production deployment guidance and troubleshooting section
- Add architecture documentation with database structure and document format examples

## Configuration Cleanup
- Remove unnecessary `database` field from CouchDB configuration
- Add `m2c_` prefix to all CouchDB database names for better namespace isolation
- Update GenerateAccountDBName() to consistently prefix databases with `m2c_`
- Clean up all configuration examples to remove deprecated database field

## Test Environment Simplification
- Simplify test script structure to eliminate confusion and redundancy
- Remove redundant populate-test-messages.sh wrapper script
- Update run-tests.sh to be comprehensive automated test with cleanup
- Maintain clear separation: automated tests vs manual testing environment
- Update all test scripts to expect m2c-prefixed database names

## Configuration Examples Added
- config-simple.json: Basic single Gmail account setup
- config-advanced.json: Multi-account with complex filtering and different providers
- config-providers.json: Real-world configurations for Gmail, Outlook, Yahoo, iCloud

## Benefits
- Clear documentation for users from beginner to advanced
- Namespace isolation prevents database conflicts in shared CouchDB instances
- Simplified test workflow eliminates user confusion about which scripts to use
- Comprehensive examples cover common email provider configurations

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

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

test/README.md

@@ -11,16 +11,17 @@ The test environment provides:
 
 ## Quick Start
 
-### Run Full Integration Tests
+### Run Basic Integration Tests
 ```bash
 ./run-tests.sh
 ```
-This will:
-1. Start all containers
-2. Populate test data
-3. Run mail2couch
-4. Verify results
-5. Clean up
+This comprehensive test will:
+1. Start all containers with cleanup
+2. Populate test data  
+3. Build and run mail2couch
+4. Verify database creation and document storage
+5. Test incremental sync behavior
+6. Clean up automatically
 
 ### Run Wildcard Pattern Tests
 ```bash
@@ -32,20 +33,56 @@ This will test various wildcard folder patterns including:
 - `*/Drafts` (subfolder patterns)
 - Complex include/exclude combinations
 
-### Manual Testing
+### Run Incremental Sync Tests
 ```bash
-# Start test environment
+./test-incremental-sync.sh
+```
+This will test incremental synchronization functionality:
+- First sync establishes baseline
+- New messages are added to test accounts
+- Second sync should only fetch new messages
+- Sync metadata tracking and IMAP SEARCH with SINCE
+
+### Manual Testing Environment
+```bash
+# Start persistent test environment (for manual experimentation)
 ./start-test-env.sh
 
-# Run mail2couch manually
+# Run mail2couch manually with different configurations
 cd ../go
 ./mail2couch -config ../test/config-test.json
+./mail2couch -config ../test/config-wildcard-examples.json
 
 # Stop test environment when done
 cd ../test
 ./stop-test-env.sh
 ```
 
+## Test Scripts Overview
+
+### Automated Testing (Recommended)
+- **`./run-tests.sh`**: Complete integration test with automatic cleanup
+  - Starts containers, populates data, runs mail2couch, verifies results
+  - Tests basic functionality, database creation, and incremental sync
+  - Cleans up automatically - perfect for CI/CD or quick validation
+
+### Specialized Feature Testing  
+- **`./test-wildcard-patterns.sh`**: Comprehensive folder pattern testing
+  - Tests `*`, `Work*`, `*/Drafts`, and complex include/exclude patterns
+  - Self-contained with own setup/teardown
+- **`./test-incremental-sync.sh`**: Incremental synchronization testing
+  - Tests sync metadata tracking and IMAP SEARCH with SINCE
+  - Multi-step validation: baseline sync → add messages → incremental sync
+  - Self-contained with own setup/teardown
+
+### Manual Testing Environment
+- **`./start-test-env.sh`**: Start persistent test containers
+  - Keeps environment running for manual experimentation
+  - Populates test data once
+  - Use with different configurations for development
+- **`./stop-test-env.sh`**: Clean up manual test environment
+  - Only needed after using `start-test-env.sh`
+
 ## Test Accounts
 
 The test environment includes these IMAP accounts:
@@ -79,11 +116,11 @@ Each account contains:
 
 ## Database Structure
 
-mail2couch will create separate databases for each mail source:
-- `wildcard_all_folders_test` - Wildcard All Folders Test (archive mode)
-- `work_pattern_test` - Work Pattern Test (sync mode)  
-- `specific_folders_only` - Specific Folders Only (archive mode)
-- `subfolder_pattern_test` - Subfolder Pattern Test (archive mode)
+mail2couch will create separate databases for each mail source (with `m2c_` prefix):
+- `m2c_wildcard_all_folders_test` - Wildcard All Folders Test (archive mode)
+- `m2c_work_pattern_test` - Work Pattern Test (sync mode)  
+- `m2c_specific_folders_only` - Specific Folders Only (archive mode)
+- `m2c_subfolder_pattern_test` - Subfolder Pattern Test (archive mode)
 
 Each database contains documents with:
 - `mailbox` field indicating the origin folder
@@ -154,17 +191,17 @@ Includes all subfolders under Work and Archive, but excludes any Drafts subfolde
 
 ```
 test/
-├── podman-compose.yml          # Container orchestration
-├── config-test.json            # Main test configuration with wildcard examples
+├── podman-compose.yml            # Container orchestration (GreenMail + CouchDB)
+├── config-test.json              # Main test configuration with wildcard examples
 ├── config-wildcard-examples.json # Advanced wildcard patterns
-├── test-wildcard-patterns.sh   # Wildcard pattern testing script
-├── run-tests.sh               # Full integration test
-├── start-test-env.sh          # Start environment
-├── stop-test-env.sh           # Stop environment
-├── populate-greenmail.py      # Create test messages with folders
-├── populate-test-messages.sh  # Wrapper script
-├── dovecot/                   # Dovecot configuration (legacy)
-└── README.md                 # This file
+├── run-tests.sh                  # Automated integration test (recommended)
+├── test-wildcard-patterns.sh     # Specialized wildcard pattern testing
+├── test-incremental-sync.sh      # Specialized incremental sync testing
+├── start-test-env.sh             # Start persistent test environment
+├── stop-test-env.sh              # Stop test environment
+├── populate-greenmail.py         # Create test messages across multiple folders
+├── dovecot/                      # Dovecot configuration (legacy, unused)
+└── README.md                     # This file
 ```
 
 ## Prerequisites