fix(views): wrap My Files table for mobile horizontal scroll

The table at /files was wider than the viewport on iPhone-class widths
(~375 px) — the rightmost column with the Copy and Delete buttons clipped
off-screen with no scroll affordance. Wrapping the table in a
.table-wrap div with overflow-x: auto lets the table scroll within
itself; moving the outer border to the wrapper preserves the desktop
visual unchanged.

- public/style.css: add .table-wrap rule, move border off table, add
  min-width: 100% so the table still fills wide viewports.
- src/views/file-list.ts: wrap <table> in <div class="table-wrap">.
- tests/integration/pages.test.ts: assert rendered HTML contains
  class="table-wrap".

tests/integration/pages.test.ts

@@ -223,6 +223,7 @@ describe('GET /files — copy link', () => {
     const res = await ctx.app.inject({ method: 'GET', url: '/files', cookies: { token } });
     expect(res.statusCode).toBe(200);
     expect(res.body).toContain('Copy link');
+    expect(res.body).toContain('class="table-wrap"');
   });
 });