bench: add WASM init and startup timing benchmarks

Adds bench/startup.bench.ts with 6 cases covering cold compile,
instantiation, createTermNative, createInputNative, createTerm,
and full module-to-first-render startup time. Also exports `bytes`
from wasm.ts so the compile step can be benchmarked independently.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: natemoo-re

bench/mod.ts

@@ -1,3 +1,4 @@
 import "./input.bench.ts";
 import "./render.bench.ts";
 import "./ops.bench.ts";
+import "./startup.bench.ts";

bench/startup.bench.ts

@@ -0,0 +1,51 @@
+import { Bench } from "tinybench";
+import { withCodSpeed } from "@codspeed/tinybench-plugin";
+import { bytes, compiled } from "../wasm.ts";
+import { createTermNative } from "../term-native.ts";
+import { createInputNative } from "../input-native.ts";
+import { createTerm } from "../term.ts";
+import { close, grow, open, text } from "../ops.ts";
+import type { Op } from "../ops.ts";
+
+const helloOps: Op[] = [
+  open("root", { layout: { width: grow(), height: grow(), direction: "ttb" } }),
+  text("Hello, World!"),
+  close(),
+];
+
+let bench = withCodSpeed(new Bench());
+
+bench
+  .add("wasm compile", async () => {
+    await WebAssembly.compile(bytes);
+  })
+  .add("wasm instantiate", async () => {
+    const memory = new WebAssembly.Memory({ initial: 2 });
+    await WebAssembly.instantiate(compiled, {
+      env: { memory },
+      clay: {
+        measureTextFunction() {},
+        queryScrollOffsetFunction(ret: number) {
+          const v = new DataView(memory.buffer);
+          v.setFloat32(ret, 0, true);
+          v.setFloat32(ret + 4, 0, true);
+        },
+      },
+    });
+  })
+  .add("createTermNative (80x24)", async () => {
+    await createTermNative(80, 24);
+  })
+  .add("createInputNative", async () => {
+    await createInputNative(50);
+  })
+  .add("createTerm (80x24)", async () => {
+    await createTerm({ width: 80, height: 24 });
+  })
+  .add("startup: createTerm + first render (80x24)", async () => {
+    const term = await createTerm({ width: 80, height: 24 });
+    term.render(helloOps);
+  });
+
+await bench.run();
+console.table(bench.table());

tasks/bundle-wasm.ts

@@ -4,7 +4,7 @@ const wasm = await Deno.readFile("clayterm.wasm");
 const base64 = encodeBase64(wasm);
 
 const source = `const bin = atob("${base64}");
-const bytes = new Uint8Array(bin.length);
+export const bytes = new Uint8Array(bin.length);
 for (let i = 0; i < bin.length; i++) bytes[i] = bin.charCodeAt(i);
 export const compiled = await WebAssembly.compile(bytes);
 `;