feat(web): drop the XP block from the combat victory screen

Design ruling R16: the victory screen removes the data-reward-experience
element and its "Erfahrung" line outright rather than hiding them behind
a conditional. CombatReward is now { silver, items }.

The surviving spec assertion checks that [data-reward-experience] is
absent, so it would genuinely fail if the block came back -- rather than
merely observing that some text changed.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

apps/web/src/app/features/combat/combat-page/combat-page.component.html

@@ -140,10 +140,6 @@
               <h3 class="rewards__title">Belohnungen</h3>
 
               <dl class="rewards__currencies">
-                <div class="rewards__currency" data-reward-experience>
-                  <dt>Erfahrung</dt>
-                  <dd>+{{ rewards.experience }} XP</dd>
-                </div>
                 <div class="rewards__currency" data-reward-silver>
                   <dt>Silber</dt>
                   <dd>+{{ rewards.silver }}</dd>