fix(desktop): route compact preview geometry fixture through media proxy (#5799)

**Category:** fix (CI)
**User Impact:** None — test-only change that unblocks `main` and every
open PR.

**Problem:** `main` has been red since #5629 landed on `45f4b91a3`:
`Desktop Smoke E2E (3)` fails `compact link preview image geometry
truncates long titles to one line` on every build (main run 31727837133,
and e.g. #5792, #5790). Two independently-green PRs raced: #5629 added
the test stubbing its preview image at the raw relay origin
(`http://localhost:3000/media/*.png`), while #5627 rewrites sent
snapshot media through the authenticated local media proxy
(`http://127.0.0.1:54321` in the E2E mock bridge). Merged together, the
image request goes to the proxy origin, the stub never matches, and
`naturalWidth` stays `0`.

**Solution:** Point the route stub at the mock proxy origin, matching
the existing `sent link preview media uses the authenticated proxy in
compact and rich cards` test in the same spec.

**Testing:** Reproduced the failure locally on `45f4b91a3`, then with
this fix: targeted test passes, and the full `messaging.spec.ts` smoke
suite passes 58/58.

Signed-off-by: Thomas Petersen <thomasp@squareup.com>
Co-authored-by: Wintermute <3f1797424fd9ad6653a83665c660517777cd7f8c228c0d5907f49e01537f3ca5@buzz.block.builderlab.xyz>

desktop/tests/e2e/messaging.spec.ts

@@ -1312,7 +1312,10 @@ test("compact link preview image geometry truncates long titles to one line", as
   page,
 }) => {
   const previewUrl = "https://github.com/block/buzz/pull/3246?geometry=1";
-  await page.route("http://localhost:3000/media/*.png", (route) =>
+  // Sent snapshot media is relay-hosted and rewritten through the
+  // authenticated media proxy (#5627), so serve the fixture from the mock
+  // proxy origin rather than the raw relay origin.
+  await page.route("http://127.0.0.1:54321/media/**", (route) =>
     route.fulfill({
       body: LINK_PREVIEW_IMAGE,
       contentType: "image/png",