Remove supplied agents and skills from the workshop template

[GeekTrainer]

Description

Prepare the template for learners to create their own skills and custom agents rather than starting with supplied answers. Preserve direct npm verification, repository instructions, and safe setup/troubleshooting guidance.

This draft depends on open #91. Its intended base is geektrainer/pr-91-base, an upstream dependency branch pinned exactly to #91's head 085d9e5009af280d51f1c8fe5a4c938a5f8a3a62. After #91 lands, retarget this PR to main and revalidate its diff and checks before merging. Do not merge this dependency branch or enable auto-merge.

Related Issue

Related to #9 (coding standards); preserves #91's conditional-skill lint intent. Companion curriculum change: github-samples/copilot-workshops#167. Workshop runtime/model validation is ongoing and is not claimed complete here.

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to change)
• 📚 Documentation update
• 🧪 Test update
• 🔧 Refactor (no functional changes)

The compatibility change is removal of repository-supplied Copilot customizations, not application behavior.

Changes Made

• Remove Accessibility, PR Readiness, and SEO profiles, plus the quality-checks and make-contribution skills and their bundled assets.
• Retain generic preference for applicable available skills with explicit direct npm fallback; retain lint, unit, E2E, and type-check requirements.
• Preserve safe setup/troubleshooting in README, remove supplied-agent claims, and clarify that the absent scripts directory is root-level.
• Keep application code, database tooling, tests, npm scripts, CI, and the Database Explorer canvas unchanged. No replacement profiles, scripts, learner trial fixtures, or logs are included.

Testing

Validated in the existing isolated cleanup worktree before committing: npm run lint; npm run typecheck:all (zero errors/warnings); npm run test:unit (27 passed); CI=true npm run test:e2e (21 passed, builds and previews fresh output without reusing another server); git diff --check. Reference, file-scope, customization absence, and local Markdown-link checks passed. No dependencies were installed. npm emitted an existing unknown-global-config warning.

Data Layer Changes

No data-layer or schema changes; test additions and migrations are not applicable.

• Ran npm run test:unit - all tests pass
• Added/updated Vitest tests for data-layer changes
• Generated a migration (npm run db:generate) for any schema change

Frontend Changes

No frontend changes; new interactive-element test IDs are not applicable.

• Ran npm run test:e2e - all tests pass
• Added data-testid attributes to interactive elements
• Verified build succeeds (npm run build)

Checklist

• My code follows the project's coding standards
• I have used explicit TypeScript types for function parameters and return values
• I have built the UI with Astro components and Tailwind CSS utility classes (dark theme)
• I have updated documentation (README, instruction files) if needed
• My changes are focused on a single concern
• I have written clear commit messages explaining what and why

TypeScript and UI checklist items are not applicable to this template/documentation cleanup.

Additional Notes

Cleanup commit: 525b74ef427a6d755b387c3e2c52e4d155e7e4af. The reviewed 11-file patch was verified against frozen SHA-256 213db0802c51b0ba9e1bc19a298e4667d55dbdde6820166ef460da31e0b8dca6 before committing. Coordinate release with github-samples/copilot-workshops#167 so lessons no longer assume the removed profiles exist. This draft does not enable merging, auto-merge, or Agent Merge.