fix(test): drop a committed scratch probe, and close a hole in the guard

Code review, all three findings valid.

e2e/tests/__m.spec.ts was a throwaway probe used to measure the mobile
hero geometry. It asserts nothing, so it could never fail; it carried a
leftover `pick('form').constructor === Object ? null : null` that is
null either way and throws if no form matches; and it should never have
been committed. Deleted.

It survived because `rm -f e2e/tests/__m.spec.ts` ran with the shell
already inside e2e/, so the path resolved to e2e/e2e/tests/... — which
does not exist, and rm -f is silent about that. `git add -A` then swept
it in. I checked `git diff --stat` before committing, which lists only
tracked modifications and never shows an untracked file; `git status
--short` would have.

The scoping guard compared the last line of a rule's prelude against the
literal '.filterBar', so a regression written as a selector list —
`.filterBar, .other { padding }`, or the same split across two lines —
would have walked straight past the test meant to catch it. Selectors
are now split on commas and matched individually, and comments are
stripped first so a brace inside one cannot desynchronise the parse.

Verified against all three shapes: bare, inline comma list, and
multi-line comma list. Each is caught; each passes again once reverted.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015mWQnpye9F299NVRCCSRvj

e2e/tests/__m.spec.ts

@@ -1,36 +0,0 @@
-import { test } from '@playwright/test';
-test('mobile hero geometry', async ({ page }) => {
-  await page.setViewportSize({ width: 390, height: 844 });
-  await page.goto('/');
-  const out = await page.evaluate(() => {
-    const pick = (sel: string) => {
-      const el = document.querySelector(sel) as HTMLElement | null;
-      if (!el) return null;
-      const r = el.getBoundingClientRect();
-      const cs = getComputedStyle(el);
-      return { left: Math.round(r.left), right: Math.round(r.right),
-               width: Math.round(r.width), height: Math.round(r.height),
-               pad: cs.padding, cls: el.className.toString().slice(0, 40) };
-    };
-    const input = document.querySelector('input[type="search"]') as HTMLElement;
-    const box = input?.closest('div');
-    const form = input?.closest('form');
-    return {
-      h1: pick('h1'),
-      lede: pick('h1 + p') ?? pick('p'),
-      omniBox: box ? { left: Math.round(box.getBoundingClientRect().left),
-                       width: Math.round(box.getBoundingClientRect().width),
-                       pad: getComputedStyle(box).padding,
-                       dir: getComputedStyle(box).flexDirection,
-                       cls: box.className.toString().slice(0,40) } : null,
-      input: pick('input[type="search"]'),
-      form: form ? { left: Math.round(form.getBoundingClientRect().left),
-                     width: Math.round(form.getBoundingClientRect().width),
-                     pad: getComputedStyle(form).padding,
-                     cls: form.className.toString().slice(0,40) } : null,
-      filterBar: pick('form').  // placeholder
-        constructor === Object ? null : null,
-    };
-  });
-  console.log(JSON.stringify(out, null, 2));
-});