feat: Add interactive CLI installer for multi-agent rule setup (npx)

[inariku]

Summary

Currently, setting up AI-DLC rules for each coding agent requires manually copying files to different locations as described in the README. This is tedious, especially when supporting multiple agents in the same project.

Proposal

Add an interactive CLI tool (npx @aidlc/install or similar) that:

1. Auto-detects installed agents by scanning the project directory (.kiro/, .amazonq/, .cursor/, etc.)
2. Interactively prompts users to select which agents to install rules for (with detected agents pre-selected)
3. Installs rules to the correct paths for each agent, exactly matching the README instructions:
   • Kiro → .kiro/steering/aws-aidlc-rules + .kiro/aws-aidlc-rule-details
   • Amazon Q → .amazonq/rules/aws-aidlc-rules + .amazonq/aws-aidlc-rule-details
   • Cursor → .cursor/rules/ai-dlc-workflow.mdc (with frontmatter) + .aidlc-rule-details/
   • Cline → .clinerules/core-workflow.md + .aidlc-rule-details/
   • Claude Code → CLAUDE.md + .aidlc-rule-details/
   • GitHub Copilot → .github/copilot-instructions.md + .aidlc-rule-details/
4. Supports symlink and copy modes
5. Tracks installations via a lock file for clean uninstall
6. CI-friendly with --yes, --agent, --copy flags for non-interactive use
7. Supports uninstall (remove command) and listing (list command)

UX (similar to Vercel Skills CLI)

$ npx @aidlc/install

┌  AI-DLC Rules Installer
│
◇  Agent Detection
│  Detected: Kiro, Claude Code
│
◆  Select agents to install rules for:
│  ● Kiro              .kiro/steering/ (detected)
│  ○ Amazon Q Developer .amazonq/rules/
│  ● Claude Code       CLAUDE.md (detected)
│  ○ Cursor IDE        .cursor/rules/ai-dlc-workflow.mdc
│  ○ Cline             .clinerules/
│  ○ GitHub Copilot    .github/copilot-instructions.md
│
◆  Installation mode:
│  ● Symlink (recommended)
│  ○ Copy
│
└  Done! Restart your agent to load the new rules.

Alignment with Tenets

• No duplication: Single source of truth in aidlc-rules/, installed to each agent path
• Methodology first: npx requires no pre-installation — Node.js only
• Agnostic: Supports all 6 documented agents
• Human in the loop: Interactive confirmation before install

Reference Implementation

I have a working implementation at https://github.com/inariku/aidlc-workflows/tree/main/cli using @clack/prompts (same UI library as Vercel Skills CLI). Happy to submit a PR if there is interest.