fix(plan): make Plán prací usable on mobile + dev port → 3050

Mobile work-plan (Plán prací) responsive fixes — desktop unchanged:
- Toolbar stacks into clean full-width rows on ≤640px (nav group,
  centered range label, full-width segmented view toggle, full-width
  category button); drops the fixed 230px label min-width and the
  margin-left:auto that made the toolbar ragged on phones.
- Grid scroll container: 100dvh-based max-height, momentum scroll, and
  overscroll containment so a fling does not bounce the whole page.
- ≤480px tightens columns (date col 72px via the colgroup <col>, person
  cols 132px) so ~2 people are comfortably visible at 360–390px.
- Touch (@media hover:none): faint persistent + on empty editable
  cells, since the hover-reveal add hint never fires on a phone.

Dev: `npm run dev` (backend) now listens on 3050 instead of 3000 to
avoid colliding with other local apps; CLAUDE.md dev-port note updated.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/server.ts

@@ -220,7 +220,9 @@ async function start() {
   }
 
   // --- Start ---
-  const port = config.isProduction ? config.port : 3000;
+  // Dev listens on a fixed local port (prod uses config.port / the PORT env).
+  // 3050 keeps it clear of other local apps that commonly grab 3000.
+  const port = config.isProduction ? config.port : 3050;
   try {
     await app.listen({ port, host: config.host });
     app.log.info(`Server running on http://${config.host}:${port}`);