fix: German quote style U+201C instead of U+201D (A11-T1)

Corrected closing quotation mark in hx-confirm attribute and test assertions
from U+201D (RIGHT DOUBLE QUOTATION MARK) to U+201C (LEFT DOUBLE QUOTATION
MARK), matching German typographic convention („...") and house style (line 114).

Changes by code point:
- finance/app/templates/szenarien.html line 17: 1 × U+201D → U+201C
- finance/tests/test_gui.py lines 501, 521: 2 × U+201D → U+201C

Template lines 17 and 114 now have identical quote code points: U+201E...U+201C.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

finance/app/templates/szenarien.html

@@ -14,7 +14,7 @@
       · Einmalposten: {{ 'ja' if sc.include_planned else 'nein' }}
       <button type="button" onclick="toggleEdit('sc', {{ sc.id }}, true)">Bearbeiten</button>
       <button type="button" hx-delete="/api/scenarios/{{ sc.id }}" hx-swap="none"
-              hx-confirm="Szenario „{{ sc.name }}” mit allen Einträgen wirklich löschen?"
+              hx-confirm="Szenario „{{ sc.name }}“ mit allen Einträgen wirklich löschen?"
               hx-on::after-request="if(event.detail.successful){window.location.reload()}">Löschen</button>
     </p>
     <div id="sc-edit-{{ sc.id }}" hidden>