chore: add agent behavior issue template

[ankitranjan7]

Summary

• add a GitHub issue form for agent behavior / CLI gap reports
• capture current Webcmd state, observed agent behavior, failure model, solution directions, senior-review questions, acceptance criteria, and non-goals

Verification

• Parsed .github/ISSUE_TEMPLATE/agent_behavior_issue.yml with js-yaml

Related issue triage

• Closed stale plugin install: github:agentrhq/webcmd installs 122 plugins with no warning #380 and browser: window.open does not appear in browser tabs #375 after verifying current origin/main behavior
• Updated still-relevant user-authored browser run: generated blob downloads need reliable artifact capture #379, browser: SESSION_BUSY needs hosted parity; data: storage needs a clear contract #378, Skill/CLI version drift between npm and Claude Code plugin install paths #274, and feature: add true headless mode for browser-backed commands #67 with the same issue schema

[github-actions]

🟠 Maintainer review suggested — low confidence

The automated review could not reach a fully supported conclusion.

Limitations

• The automated review returned an invalid structured result.

This review is advisory and does not block merging.