perf(build): budget the runtime on what ships, not on source bytes

The runtime budgets measured raw source, which counts comments -- and the
production build minifies, so comments cost a visitor nothing. The metric
therefore rewarded deleting explanatory comments over writing smaller code,
and could not tell a real feature from a wall of prose.

They now measure the minified output, which is what is actually served:
/__wrnexus/reactive.js is its own file, minified, with an immutable year-long
cache. The reactive runtime is 69684 minified against a 80000 budget, from
175246 raw -- roughly 21kB gzipped, fetched once.

Also fixes two real bugs found while testing the showcase:

  - object-valued props were serialised as a bare {...} attribute, which the
    compiler read as interpolation and tried to parse as JavaScript. That
    returned 500 for /components/navbar. Arrays start with [ and were never
    affected, which is why only object props broke. All 108 pages now render.

  - the runtime walked text nodes inside textarea, script and style, so a
    JSON sample in a textarea was evaluated away.

Navbar styles move out of ui.css into the component, matching the rest of the
navigation group. No declarations changed: 4519 before and after.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

packages/csr/test/reactive.test.ts

@@ -1052,3 +1052,18 @@ test("an empty or false roving attribute opts the group out entirely", () => {
   a.dispatchEvent(keydown(win, "ArrowRight"));
   expect(doc.activeElement!.id).toBe("a");
 });
+
+test("json inside a textarea is left alone, not read as mustaches", () => {
+  const win = mount(
+    `<div data-scope="count: 7">
+       <textarea id="editor">{"id":"a-1","count":3}</textarea>
+       <span id="out">{count}</span>
+     </div>`,
+  );
+  const doc = win.document;
+  // The surrounding scope still interpolates normally...
+  expect(doc.querySelector("#out")!.textContent).toBe("7");
+  // ...but the textarea holds data, and an expression engine would have
+  // evaluated {"id":"a-1","count":3} away and left it empty.
+  expect(doc.querySelector("#editor")!.textContent).toBe('{"id":"a-1","count":3}');
+});