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/src/index.ts

@@ -0,0 +1 @@
+// CLI entry point

packages/bin/src/index_test.ts

@@ -0,0 +1,6 @@
+import { describe, test } from "bun:test";
+
+describe("cli", () => {
+  test.todo("exits with non-zero code when no file argument is given");
+  test.todo("exits with non-zero code when file does not exist");
+});

packages/bin/src/integration_test.ts

@@ -0,0 +1,5 @@
+import { describe, test } from "bun:test";
+
+describe("cli — integration", () => {
+  test.todo("invokes core parser and produces output for a real fixture file");
+});

packages/bin/src/smoke_test.ts

@@ -0,0 +1,6 @@
+import { describe, test } from "bun:test";
+
+describe("smoke", () => {
+  test.todo("kitchen --help exits with code 0");
+  test.todo("kitchen parse <fixture> outputs structured JSON covering all annotation types");
+});