Stage 17 round 6 fixes: pin the nudge button right; schematic USSR flag emblem

- Chat: always render the (possibly empty) flex:1 caption before the nudge button, so the
  nudge stays pinned right whether or not the cooldown text shows (it drifted left when
  available).
- USSR flag: redraw the hammer & sickle as a thin schematic sketch — an elongated
  semicircle sickle with a handle, crossed by a T-shaped hammer (per the original's
  structure), instead of the bold over-filled emblem; the star is a touch smaller.

ui/src/game/Chat.svelte

@@ -57,7 +57,8 @@
       />
       <button class="iconbtn" onclick={send} disabled={busy} aria-label={t('chat.send')}>⬆️</button>
     {:else}
-      {#if nudgeOnCooldown}<span class="cooldown">{t('chat.awaitingReply')}</span>{/if}
+      <!-- A flex:1 caption keeps the nudge pinned right whether or not the cooldown text shows. -->
+      <span class="cooldown">{nudgeOnCooldown ? t('chat.awaitingReply') : ''}</span>
       <button class="iconbtn" onclick={onnudge} disabled={busy || nudgeOnCooldown} aria-label={t('chat.nudgeAction')}>🛎️</button>
     {/if}
   </div>