Extend init command into an interactive QuickStart wizard

[Copilot]

deploy4j init was a fire-and-forget command that created stub files with no project-specific configuration. This extends it into a guided interactive setup that collects server details, secret names, and AI agent preferences upfront.

Changes

Core (deploy4j-core)

• InitConfig (new) — value object capturing hostname, extraSecretNames, and agentType (COPILOT | CLAUDE | NONE)
• Initializer — new init(InitConfig) overload; old init(boolean) delegates to it with defaults
  • Substitutes hostname into deploy.yml template (- localhost → - <hostname>)
  • Appends extra secret names to the generated secrets file
  • Creates/appends agent skills to .github/copilot-instructions.md or CLAUDE.md with a duplication guard (AGENT_SKILLS_MARKER)
• Templates — added copilot-skills.md and claude-skills.md with deploy4j deployment reference content

CLI (deploy4j-cli)

• InitCliCommand — replaces silent execution with a 3-step interactive flow:
  1. Server IP/hostname (defaults to localhost)
  2. Secret env var names (comma-separated, optional)
  3. AI agent skills — auto-detects Copilot (.github/copilot-instructions.md) or Claude (CLAUDE.md) and prompts to append skills

👋 Welcome to deploy4j init!
   Let's get your project set up for deployment.

? Server IP address or hostname [localhost]: 192.168.1.100

? Secret environment variable names (comma-separated, press Enter to skip): DB_PASSWORD,API_KEY

? Detected GitHub Copilot — add deploy4j skills? [Y/n]: Y

📁 Setting up files...

✅ Done! Next steps:
   1. Review and edit config/deploy.yml
   2. Fill in your secrets in .deploy4j/secrets
   3. Run 'deploy4j setup <version>' for first-time deployment

Tests & Docs

• New InitializerTest cases cover: hostname substitution, extra secrets appended, Copilot/Claude file creation, no-duplication on repeated runs, null-hostname defaulting
• docs/_commands/init.md updated with the interactive Q&A and a files-created table
• README.md QuickStart updated to call deploy4j init immediately after install

Original prompt

I'd like the init command to be extended.

I want an interactive process to do the following.

1 init the deploy.yml
2 init the secrets file
3 init an ai agent skills file

For each, we should check if they already exist otherwise create if confirmed by the user.

Ask for QuickStart details

1 up address or hostname
2 any upfront secrets environment var names
3 depending on what agent ref we can find Claude/copilot confirm with user and put skill there

Use a friendly helpful tone for questions.

Update the unit command documentation with the expected questions. Potentially update any QuickStart quite to use the init command after install

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💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.