test: the page-menu spec reads the demo under the decimal default

`harness/tests/pages.spec.js` arrived on `main` with #123 while this branch was
open, and asserts `toHaveText("20,300")` against `web/demo.improv`. The merge
was clean and the combination was wrong — design-principles §7's third case
exactly: `git merge-tree` answers "can git combine these texts", not "does the
combination do what both sides meant". CI caught it on the merge ref, which is
the only place the two sides had ever been run together.

The assertion is unchanged in what it discriminates: it exists so that a menu
moving only the label fails, and `"20,300.00"` separates Q4 from Q1's
`"18,400.00"` exactly as the old literal did.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FC2jVn8Au7E9JPkw6bwXXH

harness/tests/pages.spec.js

@@ -58,7 +58,7 @@ test.describe("a page axis can be picked from a menu", () => {
     // Espresso Revenue is 18,400 in Q1 and 20,300 in Q4, so a menu that moved
     // only the label would leave this unchanged.
     await expect(firstCell).not.toHaveText(q1 ?? "");
-    await expect(firstCell).toHaveText("20,300");
+    await expect(firstCell).toHaveText("20,300.00");
   });
 
   // The menu is operable without a mouse, and while it is open it owns the