feat: add Kiro agent (kiro-cli)

[mikeaadd]

Summary

This is a work-in-progress experimentl. I'm a novice Go developer who wanted to add Kiro support and used Claude Code to help build it.

• Implements the Agent interface for Kiro CLI (kiro-cli)
• Prompt passed as a positional arg to kiro-cli chat --no-interactive
• Agentic mode adds --trust-all-tools
• WithModel is a no-op — kiro-cli has no --model flag
• Adds Kiro to auto-discovery fallback order and help/error strings
• Tests mirror the patterns used by other agents

Test plan

• go test ./internal/agent/ passes
• go test ./... green
• roborev review --local --agent kiro --wait HEAD produces a review

[roborev-ci]

roborev: Combined Review (a270c120)

Verdict: One Medium-severity issue was found; otherwise the reviewed changes look solid.

Medium

1. Prompt argument can be misparsed as CLI flag — internal/agent/kiro.go:74
prompt is appended as a positional argument without an option terminator (--). If a prompt starts with -, kiro-cli may treat it as a flag instead of user content, which can cause incorrect behavior or failures.
   Suggested fix: append -- before the prompt if supported (args = append(args, "--", prompt)), or reject leading-- prompts with a clear validation error.

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Synthesized from 4 reviews (agents: gemini, codex | types: security, default)

[roborev-ci]

roborev: Combined Review (07e2146e)

Verdict: One medium-severity parsing issue should be addressed before merge; no critical or high findings were identified.

Medium

1. Potential truncation of valid review content
   File: internal/agent/kiro.go:27
stripKiroOutput treats the first line starting with "> " as a start marker unconditionally. If Kiro output has no true marker but includes markdown blockquotes, earlier content can be dropped, including real findings.
   Recommendation: Only treat this as a marker in a constrained/expected position (for example, first non-empty line after known chrome); otherwise return the full ANSI-stripped output.

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Synthesized from 4 reviews (agents: codex, gemini | types: security, default)

[roborev-ci]

roborev: Combined Review (11d3e55e)

Verdict: PR has 2 Medium-severity issues to address before merge; no Critical/High findings were reported.

Medium

1. Potential output truncation/misparse due to loose start-marker detection

   • Location: internal/agent/kiro.go:32
   • Issue: stripKiroOutput treats the first "> " marker (within first 30 lines) as the start of real content. If the expected preamble marker is missing/changed and a normal blockquote appears early, valid content before that point can be dropped.
   • Suggested fix: Tighten marker detection (require a more specific signature/preamble) and add a test for “no marker present but early blockquote exists.”

2. Large diffs can fail due to OS argument length limits (ARG_MAX)

   • Location: internal/agent/kiro.go:117 (also noted around prompt append logic)
   • Issue: Passing the full review prompt as a CLI argument (args = append(args, prompt)) can fail for large inputs on some systems.
   • Suggested fix: Prefer stdin or temp-file input if kiro-cli supports it; otherwise add explicit handling/error guidance for oversized prompts.

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Synthesized from 4 reviews (agents: codex, gemini | types: security, default)

[wesm]

closing in favor of #419