feat(cli): implement iterate agents list — detect installed AI CLIs

[forgou37]

Closes #464.

Summary

Replaces the hardcoded stub in sh1pt iterate agents list with real binary detection.

Before

$ sh1pt iterate agents list
  ○ claude  run `sh1pt agents setup --agent claude`
  ○ codex   run `sh1pt agents setup --agent codex`
  ○ qwen    run `sh1pt agents setup --agent qwen`

After

$ sh1pt iterate agents list
  ● claude  v1.2.3
  ○ codex   not installed — npm install -g @openai/codex
  ○ qwen    not installed — pip install qwen-agent

1/3 agent(s) installed. Run `sh1pt agents setup` to install missing agents.

$ sh1pt iterate agents list --json
[
  { "id": "claude", "installed": true, "version": "1.2.3", ... },
  ...
]

Changes

• Runs <binary> --version via exec() from @profullstack/sh1pt-core for each known agent
• Returns real installation status with version string when available
• Falls back to install hint + setup command when not found
• --json flag output now contains real data, not placeholder stubs

[greptile-apps]

Greptile Summary

This PR replaces the hardcoded stub in sh1pt iterate agents list with real binary detection, running <binary> --version via exec() for each known agent and reporting installation status with version and install hints.

• checkAgent now spawns each CLI binary and captures stdout to populate installed and version fields, with --json output reflecting real data.
• The raw stdout from --version (e.g. \"Claude Code 1.2.3\") is used as-is for the version field and then prefixed with v in the display, producing output like vClaude Code 1.2.3 instead of the intended v1.2.3; this affects both the human-readable output and the JSON payload.
• A binary that exits non-zero from --version (even though it is on PATH) is silently treated as not installed, which can produce a false negative.

Confidence Score: 3/5

The change adds no destructive side-effects, but the core feature — displaying the installed version — will produce visually broken output for every agent because the raw CLI version string is re-prefixed with v.

The version string captured from stdout is the full, unparsed output of --version (e.g. "Claude Code 1.2.3"), yet the display code prepends another v, yielding vClaude Code 1.2.3. This means the primary new capability of the feature — showing the installed version cleanly — does not work correctly for any of the three listed agents. Additionally, a binary that returns a non-zero exit code for --version will be incorrectly listed as not installed.

packages/cli/src/commands/agents.ts — version parsing and exit-code handling in checkAgent

Important Files Changed

Filename	Overview
packages/cli/src/commands/agents.ts	Replaces hardcoded stub with real binary detection via exec(); version string is taken directly from raw stdout and prefixed with v, producing malformed output like vClaude Code 1.2.3; non-zero --version exit codes also incorrectly mark a binary as not installed.

_{Reviews (1): Last reviewed commit: "feat(cli): implement iterate agents list..." | Re-trigger Greptile}

[greptile-apps]

The v prefix is prepended to the raw, un-parsed stdout of --version. In practice claude --version outputs something like "Claude Code 1.2.3" (the full tool name), so the displayed string becomes vClaude Code 1.2.3 — not the clean v1.2.3 the PR description promises. The JSON output has the same issue: version contains the entire first-line dump rather than just the semver. A simple regex extracts the version number regardless of the prefix the CLI adds.

Suggested change

	return {
	id: agent.id,
	installed: true,
	version: result.stdout.trim() || undefined,
	installHint: agent.installHint,
	authHint: agent.authHint,
	};
	const rawOut = result.stdout.trim() || result.stderr.trim();
	const semverMatch = rawOut.match(/\d+\.\d+\.\d+[\w.-]*/);
	return {
	id: agent.id,
	installed: true,
	version: semverMatch ? semverMatch[0] : rawOut || undefined,
	installHint: agent.installHint,
	authHint: agent.authHint,
	};

Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!

[greptile-apps]

When a binary exists on PATH but --version exits with a non-zero code, the function falls through the if (result.exitCode === 0) guard and returns installed: false. A handful of real CLIs (including some versions of codex) exit non-zero for --version. Treating any successful resolution (i.e., the process started at all) as installed would be more robust, since ENOENT is already handled by the outer catch.

Suggested change

	if (result.exitCode === 0) {
	return {
	id: agent.id,
	installed: true,
	version: result.stdout.trim() || undefined,
	installHint: agent.installHint,
	authHint: agent.authHint,
	};
	}
	} catch {
	// binary not found
	}
	// Binary was found (spawn succeeded); non-zero exit for --version is still "installed".
	const rawOut = (result.stdout.trim() || result.stderr.trim());
	const semverMatch = rawOut.match(/\d+\.\d+\.\d+[\w.-]*/);
	return {
	id: agent.id,
	installed: true,
	version: semverMatch ? semverMatch[0] : rawOut || undefined,
	installHint: agent.installHint,
	authHint: agent.authHint,
	};
	} catch {
	// binary not found (ENOENT) or other spawn error
	}