feat: Add agent roles and a prompt template for copilot

[marqode]

Summary

Adds 5 agent roles and one prompt template for use with Github Copilot:

• architect agent: Assist with planning new features and understanding patterns in the codebase
• debugger agent: Help to find and resolve issues
• implementer agent: Primary agent for making code changes. Useful for working through feature plan generated by explore-plan or receiving prompts from prompt-engineer
• prompt-engineer agent: Create prompts to hand off to other agents. Copied from awesome-copilot repo.
• tester agent:
• explore-plan prompt: Prompt template for planning a new feature. Creates a markdown file with the plan that other agents can update.

Release Impact

According to the Landscape Server Release Cycle, this change will target the following release cycle:

• Target Branch: dev / main (Beta)
• Version Impact:
  • Patch (Fix)
  • Minor (Feature)
  • Major (Breaking)

Checklist

• Changeset Added: I have run pnpm changeset and committed the resulting .md file.
• UI Verified: I have verified the changes locally.
• Linting: No linting errors are present (especially in scripts/).

Versioning Reminder

Important

This repository now uses CalVer ($YY.0M.Point.Patch$).
Please ensure your changeset description is clear, as it will be automatically added to the CHANGELOG.md upon merging to main.

[Copilot]

Pull request overview

Adds GitHub Copilot configuration assets (custom agents + a prompt template) intended to standardize planning, implementation, debugging, and testing workflows for Landscape UI contributors.

Changes:

• Adds five Copilot agent role definitions (architect, implementer, debugger, tester, prompt-engineer).
• Adds an explore-plan prompt template to generate feature implementation plans.
• Adds a Changesets entry to publish the update.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 10 comments.

Show a summary per file

File	Description
.github/prompts/explore-plan.prompt.md	New planning prompt template for generating feature plan markdown.
.github/agents/architect.agent.md	New architect agent role definition and planning constraints.
.github/agents/debugger.agent.md	New debugger agent role definition for troubleshooting workflows.
.github/agents/implementer.agent.md	New implementer agent role definition for executing feature plans.
.github/agents/prompt-engineer.agent.md	New prompt-engineer agent role definition for prompt refinement.
.github/agents/tester.agent.md	New tester agent role definition for Vitest/MSW test generation.
.changeset/rich-facts-follow.md	Changeset entry to publish the new Copilot assets.

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