Add structured autonomy prompts for generating, implementing, and planning implementation documentation

- Introduced `structured-autonomy-generate.prompt.md` for generating implementation plans from PRs.
- Added `structured-autonomy-implement.prompt.md` to execute implementation plans step-by-step.
- Created `structured-autonomy-plan.prompt.md` for collaborative project planning and outlining development steps.
- Implemented prompts for suggesting relevant GitHub Copilot agents, chat modes, collections, instructions, and prompts from the awesome-copilot repository.
- Developed `update-implementation-plan.prompt.md` for updating existing implementation plans with new requirements and structured output.

.github/prompts/playwright-explore-website.prompt.md

@@ -0,0 +1,19 @@
+---
+agent: agent
+description: 'Website exploration for testing using Playwright MCP'
+tools: ['changes', 'search/codebase', 'edit/editFiles', 'fetch', 'findTestFiles', 'problems', 'runCommands', 'runTasks', 'runTests', 'search', 'search/searchResults', 'runCommands/terminalLastCommand', 'runCommands/terminalSelection', 'testFailure', 'playwright']
+model: 'Claude Sonnet 4'
+---
+
+# Website Exploration for Testing
+
+Your goal is to explore the website and identify key functionalities.
+
+## Specific Instructions
+
+1. Navigate to the provided URL using the Playwright MCP Server. If no URL is provided, ask the user to provide one.
+2. Identify and interact with 3-5 core features or user flows.
+3. Document the user interactions, relevant UI elements (and their locators), and the expected outcomes.
+4. Close the browser context upon completion.
+5. Provide a concise summary of your findings.
+6. Propose and generate test cases based on the exploration.