feat: add kitchen view command and parser skeleton (task 0003)

Cut the first complete thread through both layers with the smallest set
of node types.

@kitchen-md/core gains a pure, total `parse` returning a
`DocumentAST` of `{ frontmatter, blocks, diagnostics }`, built from a
minimal remark pipeline (remark-parse + remark-frontmatter) with an
internal translation layer to core's own types. This slice models
frontmatter passthrough, HeadingBlock, ParagraphBlock, and TextNode;
remark's mdast does not surface in the public API.

@kitchen-md/bin gains the `view` subcommand (commander) that reads a
file, calls `parse`, and passes the AST to a pure `render` that returns
an ANSI-styled string via chalk (auto-suppressed off a TTY). Frontmatter
prints as raw YAML followed by a separator, headings styled distinctly
by level, paragraphs as prose. A missing argument prints usage and a
missing/unreadable file a human-readable error, both exiting 1.

Richer blocks/inline plus raw fallbacks are task 0004; malformed
frontmatter diagnostics and the basic.md smoke test are task 0007.

packages/bin/src/index.ts

@@ -1 +1,27 @@
-// CLI entry point
+#!/usr/bin/env bun
+import { readFileSync } from "node:fs";
+import { parse } from "@kitchen-md/core";
+import { Command } from "commander";
+import { render } from "./render.ts";
+
+const program = new Command();
+
+program.name("kitchen").description("Read and view KitchenMD Recipe Files");
+
+program
+  .command("view")
+  .description("Render a Recipe File to the terminal")
+  .argument("<file>", "path to a Recipe File")
+  .action((file: string) => {
+    let content: string;
+    try {
+      content = readFileSync(file, "utf8");
+    } catch (error) {
+      const reason = error instanceof Error ? error.message : String(error);
+      process.stderr.write(`kitchen: cannot read '${file}': ${reason}\n`);
+      process.exit(1);
+    }
+    process.stdout.write(render(parse(content)));
+  });
+
+program.parse();