Refactor CLI to use flags instead of positional arguments

- Change all commands to use flags (--bucket, --prefix, etc.)
- Add --config flag to backup command
- Support VAULTIK_CONFIG environment variable for config path
- Use /etc/vaultik/config.yml as default config location
- Add test/config.yaml for testing
- Update tests to use environment variable for config path
- Add .gitignore for build artifacts and local configs
- Update documentation to reflect new CLI syntax

README.md

@@ -100,20 +100,23 @@ Existing backup software fails under one or more of these conditions:
 ### commands
 
 ```sh
-vaultik backup /etc/vaultik.yaml [--cron] [--daemon]
-vaultik restore <bucket> <prefix> <snapshot_id> <target_dir>
-vaultik prune <bucket> <prefix>
-vaultik fetch <bucket> <prefix> <snapshot_id> <filepath> <target_fileordir>
-vaultik verify <bucket> <prefix> [<snapshot_id>]
+vaultik backup [--config <path>] [--cron] [--daemon]
+vaultik restore --bucket <bucket> --prefix <prefix> --snapshot <id> --target <dir>
+vaultik prune --bucket <bucket> --prefix <prefix> [--dry-run]
+vaultik fetch --bucket <bucket> --prefix <prefix> --snapshot <id> --file <path> --target <path>
+vaultik verify --bucket <bucket> --prefix <prefix> [--snapshot <id>] [--quick]
 ```
 
 ### environment
 
 * `VAULTIK_PRIVATE_KEY`: Required for `restore`, `prune`, `fetch`, and `verify` commands. Contains the age private key for decryption.
+* `VAULTIK_CONFIG`: Optional path to config file. If set, `vaultik backup` can be run without specifying the config file path.
 
 ### command details
 
 **backup**: Perform incremental backup of configured directories
+* Config is located at `/etc/vaultik/config.yml` by default
+* `--config`: Override config file path
 * `--cron`: Silent unless error (for crontab)
 * `--daemon`: Run continuously with inotify monitoring and periodic scans