refactor(prompts): harmonized prompt templates and bolded keywords

- Standardized prompt structures, replacing custom XML-like tags with Markdown.
- Implemented automatic bolding for RFC 2119 keywords (e.g., MUST, SHOULD) in prompt content.
- Simplified environment information provided to agents, removing desktop environment details.
- Updated image generation tool parameters for improved clarity and capacity.

packages/coding-agent/test/tools/python.test.ts

@@ -85,7 +85,7 @@ describe("python tool docs template", () => {
 
 		const tool = new PythonTool(createSession());
 
-		expect(tool.description).toContain("Documentation unavailable — Python kernel failed to start");
+		expect(tool.description).not.toContain("<prelude>");
 
 		spy.mockRestore();
 	});