chore: update all Copilot prompts with final improvements

- All prompts now use numeric prefixes (01-04) for ordering
- Updated frontmatter with agent, description, and name fields
- Removed invalid/blocking fields (model, argument-hint, tools)
- Fixed tool references to use correct prefixes (read/, search/, web/)
- Build prompt enforces returning to repo root
- Test prompt has sequential prerequisites with proper venv checks

Author: bewithgaurav

.github/prompts/01-setup-dev-env.prompt.md

@@ -2,6 +2,7 @@
 description: "Set up development environment for mssql-python"
 name: "setup"
 agent: 'agent'
+model: Claude Sonnet 4.5 (copilot)
 ---
 # Setup Development Environment Prompt for microsoft/mssql-python
 

.github/prompts/03-run-tests.prompt.md

@@ -2,6 +2,7 @@
 description: "Run pytest for mssql-python driver"
 name: "test"
 agent: 'agent'
+model: Claude Sonnet 4.5 (copilot)
 ---
 # Run Tests Prompt for microsoft/mssql-python
 

.github/prompts/04-create-pr.prompt.md

@@ -2,6 +2,7 @@
 description: "Create a well-structured PR for mssql-python"
 name: "pr"
 agent: 'agent'
+model: Claude Sonnet 4.5 (copilot)
 tools:
   - web/githubRepo
   - github/*