Configure only selected detected agents

[codeprakhar25]

What problem does this solve?

agentdiff configure currently behaves like a broad global setup step. That is convenient for first install, but it is not great once a machine has multiple agents installed or a user only wants to enable capture for a subset of them.

The command should detect which supported agents appear to be installed/configurable and ask the user which integrations to install.

What would you like to see?

Add dynamic agent selection to agentdiff configure.

Suggested behavior:

• Detect available agent surfaces before writing config:
  • Claude Code
  • Cursor
  • Codex CLI
  • Copilot VS Code extension
  • Windsurf
  • OpenCode
  • Gemini / Antigravity
• Interactive mode:
  • show detected agents
  • show unsupported/not-detected agents separately
  • ask which ones to configure
  • default to detected agents only
• Non-interactive flags:
  • agentdiff configure --all
  • agentdiff configure --agents cursor,claude-code,codex
  • agentdiff configure --skip copilot
  • optionally --yes for CI/bootstrap scripts
• Output a clear summary:
  • installed
  • skipped
  • not detected
  • failed with reason

Acceptance criteria

• Users can configure only selected agents.
• --all preserves today's direct install behavior.
• Existing scripts using agentdiff configure do not break.
• Detection failures are non-fatal and explain what was skipped.
• Tests cover argument parsing and at least one detected/missing agent path.

Alternatives considered

Keep configure global and tell users to manually edit agent configs after install. That is brittle and makes AgentDiff feel risky on machines with many tools installed.