Add interactive shell mode for Keep

- Implemented `keep shell` command for interactive secret management
- Persistent context (stage/vault) across commands
- Command shortcuts and aliases for efficiency
- Context switching commands (stage, vault, use)
- Command history with readline support
- Works in both interactive and non-interactive modes
- Comprehensive documentation in CLI reference
- Added PsySH dependency for future REPL enhancements

Features:
  - No need to repeatedly specify --stage and --vault
  - Quick aliases: s (stage), v (vault), g (get), d (delete), etc.
  - Partial name matching for stages and vaults
  - All standard Keep commands work in shell mode
  - Clean exit with multiple aliases (exit, quit, q)

Example:
  keep shell --stage=production
  keep> set API_KEY "value"
  keep> stage development
  keep> copy API_KEY --to=production

Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

Author: 3 people

composer.json

@@ -21,14 +21,15 @@
     ],
     "require": {
         "php": "^8.3",
+        "ext-sodium": "*",
         "illuminate/console": "^12.0",
         "illuminate/container": "^12.0",
         "illuminate/events": "^12.0",
         "illuminate/support": "^12.0",
         "laravel/prompts": "^0.3.0",
+        "psy/psysh": "^0.12.10",
         "symfony/console": "^7.0",
-        "vlucas/phpdotenv": "^5.6",
-        "ext-sodium": "*"
+        "vlucas/phpdotenv": "^5.6"
     },
     "require-dev": {
         "aws/aws-sdk-php": "^3.354",

docs/guide/reference/cli-reference.md

@@ -172,6 +172,72 @@ keep show --stage=staging --format=json
 keep show --stage=production --vault=secretsmanager --format=env
 ```
 
+## `keep shell`
+
+Start an interactive shell for Keep commands with persistent context.
+
+| Option | Type | Default | Description |
+|--------|------|---------|-------------|
+| `--stage` | string | *first configured stage* | Initial stage to use |
+| `--vault` | string | *default vault* | Initial vault to use |
+
+### Shell Mode Features
+
+The interactive shell provides:
+- **Persistent context**: No need to specify --stage and --vault for each command
+- **Command shortcuts**: Quick aliases for common commands
+- **Context switching**: Easy switching between stages and vaults
+- **Command history**: Access previous commands with arrow keys
+
+### Shell Commands
+
+**Context Management:**
+```bash
+keep> stage production    # Switch to production stage (alias: s)
+keep> vault ssm          # Switch to ssm vault (alias: v)
+keep> use ssm:production # Switch both at once (alias: u)
+keep> context            # Show current context (alias: ctx)
+```
+
+**Secret Operations:**
+```bash
+keep> set API_KEY value  # Set a secret
+keep> get API_KEY        # Get a secret (alias: g)
+keep> delete API_KEY     # Delete a secret (alias: d)
+keep> show               # List all secrets (aliases: ls, list, l)
+keep> copy KEY --to=prod # Copy using current context as source
+```
+
+**Shell Control:**
+```bash
+keep> help               # Show available commands (alias: ?)
+keep> history            # Show command history (alias: h)
+keep> clear              # Clear screen (alias: cls)
+keep> exit               # Exit shell (aliases: quit, q)
+```
+
+### Examples
+
+```bash
+# Start shell with initial context
+keep shell --stage=production --vault=ssm
+
+# Interactive session
+keep (ssm:production)> show
+keep (ssm:production)> stage development
+✓ Switched to stage: development
+keep (ssm:development)> set API_KEY "dev-key"
+keep (ssm:development)> copy API_KEY --to=production
+keep (ssm:development)> exit
+Goodbye!
+```
+
+### Tips
+- Use partial names for stages/vaults (e.g., `s prod` for `stage production`)
+- All standard Keep commands work in the shell
+- Commands automatically use the current context
+- Use tab for basic command completion (if readline is available)
+
 ## `keep delete`
 
 Remove secrets from vaults.