meta: add GitHub issue templates

[emaarco]

Summary

The repository currently has no issue templates (only a PR template). As the project grows, issue templates would help contributors file consistent, actionable reports for bugs, feature requests, and docs improvements — reducing back-and-forth for maintainers.

Suggested templates

• Bug report — reproduction steps, expected vs actual behavior, OS/version info
• Feature request — problem description, proposed solution
• Docs improvement — which doc, what's missing or wrong

These could live in .github/ISSUE_TEMPLATE/ as standard GitHub issue forms (YAML) or plain markdown templates.

Bonus: structured input for AI agents

Given that this project explicitly targets AI agents as users, consistent issue structure also creates a reliable input format for automation. Skills could be built around issue triage, reproduction, or even implementation — but only if issues follow a predictable schema. Issue templates are a low-effort way to enable that.

[emaarco]

Happy to contribute this if maintainers are interested — just let me know.