Fix integration tests: correct vault derivation index and debug test failures

README.md

@@ -175,13 +175,16 @@ Decrypts data using an Age key stored as a secret.
 │   │   │   └── database%password/       # Secret: database/password
 │   │   │       ├── versions/
 │   │   │       └── current -> versions/20231215.001
+│   │   ├── vault-metadata.json          # Vault metadata
+│   │   ├── pub.age                      # Long-term public key
 │   │   └── current-unlocker -> ../unlockers.d/passphrase
 │   └── work/
 │       ├── unlockers.d/
 │       ├── secrets.d/
+│       ├── vault-metadata.json
+│       ├── pub.age
 │       └── current-unlocker
-├── currentvault -> vaults.d/default
-└── configuration.json
+└── currentvault -> vaults.d/default
 ```
 
 ### Key Management and Encryption Flow
@@ -309,11 +312,17 @@ secret decrypt encryption/mykey --input document.txt.age --output document.txt
 - **Encryption**: Age (X25519 + ChaCha20-Poly1305)
 - **Key Exchange**: X25519 elliptic curve Diffie-Hellman
 - **Authentication**: Poly1305 MAC
+- **Hashing**: Double SHA-256 for public key identification
 
 ### File Formats
 - **Age Files**: Standard Age encryption format (.age extension)
 - **Metadata**: JSON format with timestamps and type information
-- **Configuration**: JSON configuration files
+- **Vault Metadata**: JSON containing vault name, creation time, derivation index, and public key hash
+
+### Vault Management
+- **Derivation Index**: Each vault uses a unique derivation index from the mnemonic
+- **Public Key Hash**: Double SHA-256 hash of the index-0 public key identifies vaults from the same mnemonic
+- **Automatic Key Derivation**: When creating vaults with a mnemonic, keys are automatically derived
 
 ### Cross-Platform Support
 - **macOS**: Full support including Keychain integration
@@ -351,8 +360,9 @@ make lint     # Run linter
 ### Testing
 The project includes comprehensive tests:
 ```bash
-./test_secret_manager.sh  # Full integration test suite
-go test ./...             # Unit tests
+make test     # Run all tests
+go test ./... # Unit tests
+go test -tags=integration -v ./internal/cli  # Integration tests
 ```
 
 ## Features