chore: scaffold Bun workspace monorepo

Sets up the initial project structure: two packages (@kitchen-md/core
and @kitchen-md/bin), shared tsconfig, shared fixtures, per-package
test stubs (unit, integration, smoke), .gitignore, and project
CLAUDE.md with Conventional Commits convention.

packages/bin/package.json

@@ -0,0 +1,16 @@
+{
+  "name": "@kitchen-md/bin",
+  "version": "0.0.0",
+  "private": true,
+  "type": "module",
+  "bin": {
+    "kitchen": "./src/index.ts"
+  },
+  "scripts": {
+    "test": "bun test",
+    "build": "bun build --compile ./src/index.ts --outfile kitchen"
+  },
+  "dependencies": {
+    "@kitchen-md/core": "workspace:*"
+  }
+}