feat: Introduce @automaker/prompts package for AI prompt templates

Changes:
- Added a new package, @automaker/prompts, containing AI prompt templates for enhancing user-written task descriptions.
- Implemented four enhancement modes: improve, technical, simplify, and acceptance, each with corresponding system prompts and examples.
- Updated relevant packages to utilize the new prompts package, ensuring backward compatibility with existing imports.
- Enhanced documentation to include usage examples and integration details for the new prompts.

Benefits:
✅ Streamlined AI prompt management across the codebase
✅ Improved clarity and usability for AI-powered features
✅ Comprehensive documentation for developers

All tests passing.

libs/prompts/vitest.config.ts

@@ -0,0 +1,21 @@
+import { defineConfig } from "vitest/config";
+
+export default defineConfig({
+  test: {
+    globals: true,
+    environment: "node",
+    include: ["tests/**/*.test.ts"],
+    coverage: {
+      provider: "v8",
+      reporter: ["text", "json", "html"],
+      include: ["src/**/*.ts"],
+      exclude: ["src/**/*.d.ts", "src/index.ts"],
+      thresholds: {
+        lines: 90,
+        functions: 95,
+        branches: 85,
+        statements: 90,
+      },
+    },
+  },
+});