feat: web settings restructure + popup drag + calendar management table (v52)

- Remove "Ansicht" tab; move Kalenderansicht to top of Darstellung
- Reorder Darstellung: Kalenderansicht → Sprache → Stundenhöhe → Farben
- Move Standard-Termindauer to Profil tab as contrast-button selector
- Replace per-source account sections in Kalender tab with unified
  calendar management table (Name/Herkunft/Ausgeblendet/Benachrichtigungen/
  Export·Import/Sync/Delete) covering all calendar sources
- Add "Konto hinzufügen" buttons (Lokal/CalDAV/iCal/HA/Google) to Kalender tab
- Popup drag-to-move via pointer capture on .popup-header

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/index.html

@@ -692,7 +692,6 @@
       <nav class="settings-nav">
         <button class="settings-nav-btn active" data-panel="profile" data-i18n="settings_nav_profile">Profil</button>
         <button class="settings-nav-btn" data-panel="general" data-i18n="settings_nav_appearance">Darstellung</button>
-        <button class="settings-nav-btn" data-panel="view" data-i18n="settings_nav_view">Ansicht</button>
         <button class="settings-nav-btn" data-panel="accounts" data-i18n="settings_nav_calendars">Kalender</button>
         <button class="settings-nav-btn hidden" data-panel="users" id="settings-nav-users" data-i18n="settings_nav_users">Benutzerverwaltung</button>
       </nav>
@@ -727,6 +726,16 @@
             </select>
           </div>
 
+          <h4 class="panel-title" style="margin-top:24px" data-i18n="settings_default_duration">Standard-Termindauer</h4>
+          <div class="contrast-selector" id="cfg-event-duration">
+            <button class="contrast-btn" data-val="15">15 min</button>
+            <button class="contrast-btn" data-val="30">30 min</button>
+            <button class="contrast-btn" data-val="45">45 min</button>
+            <button class="contrast-btn" data-val="60">1 h</button>
+            <button class="contrast-btn" data-val="90">1,5 h</button>
+            <button class="contrast-btn" data-val="120">2 h</button>
+          </div>
+
           <h4 class="panel-title" style="margin-top:24px" data-i18n="settings_calendars">Geteilter Kalender</h4>
           <p class="panel-desc" data-i18n="settings_group_visible_desc">Wähle, welcher deiner Kalender für deine Gruppenmitglieder sichtbar ist</p>
           <div class="form-group">
@@ -735,10 +744,35 @@
           </div>
         </div>
 
-        <!-- Darstellung: Sprache, Farben, Stundenhöhe -->
+        <!-- Darstellung: Kalenderansicht, Sprache, Stundenhöhe, Farben -->
         <div class="settings-panel" id="settings-panel-general">
 
-          <h4 class="panel-title" data-i18n="settings_language">Sprache</h4>
+          <h4 class="panel-title" data-i18n="settings_calendar_view">Kalenderansicht</h4>
+          <div class="form-group">
+            <label data-i18n="settings_default_view">Standardansicht</label>
+            <select id="cfg-default-view">
+              <option value="month" data-i18n="view_month">Monat</option>
+              <option value="week" data-i18n="view_week">Woche</option>
+              <option value="day" data-i18n="view_day">Tag</option>
+              <option value="quarter" data-i18n="view_quarter">Quartal</option>
+              <option value="agenda" data-i18n="view_agenda">Termine</option>
+            </select>
+          </div>
+          <div class="form-group">
+            <label data-i18n="settings_week_start">Erster Wochentag</label>
+            <select id="cfg-week-start">
+              <option value="monday" data-i18n="week_start_monday">Montag</option>
+              <option value="sunday" data-i18n="week_start_sunday">Sonntag</option>
+            </select>
+          </div>
+          <div class="form-group">
+            <label class="toggle-label">
+              <input type="checkbox" id="cfg-dim-past" />
+              <span data-i18n="settings_dim_past">Vergangene Termine ausgrauen</span>
+            </label>
+          </div>
+
+          <h4 class="panel-title" style="margin-top:24px" data-i18n="settings_language">Sprache</h4>
           <div class="form-group">
             <select id="cfg-language">
               <option value="de">Deutsch</option>
@@ -746,6 +780,15 @@
             </select>
           </div>
 
+          <h4 class="panel-title" style="margin-top:24px" data-i18n="settings_hour_height">Stundenhöhe (Wochen- &amp; Tagesansicht)</h4>
+          <p class="panel-desc" data-i18n="settings_hour_height_desc">Wie viel Platz eine Stunde in der Zeitrasteransicht einnimmt</p>
+          <div class="contrast-selector" id="cfg-hour-height" data-setting="hour_height">
+            <button class="contrast-btn" data-val="28"><span class="hour-preview">━━</span><span class="contrast-lbl" data-i18n="hour_compact">Kompakt</span></button>
+            <button class="contrast-btn" data-val="44"><span class="hour-preview">━━━</span><span class="contrast-lbl" data-i18n="hour_normal">Normal</span></button>
+            <button class="contrast-btn" data-val="60"><span class="hour-preview">━━━━</span><span class="contrast-lbl" data-i18n="hour_comfort">Komfort</span></button>
+            <button class="contrast-btn" data-val="80"><span class="hour-preview">━━━━━</span><span class="contrast-lbl" data-i18n="hour_large">Gross</span></button>
+          </div>
+
           <h4 class="panel-title" style="margin-top:24px" data-i18n="settings_colors">Farben</h4>
           <div class="form-group">
             <label data-i18n="settings_primary_color">Primärfarbe</label>
@@ -807,88 +850,19 @@
               <button type="button" class="btn btn-ghost btn-sm" id="cfg-bg-color-reset" data-i18n="reset" title="Zurücksetzen">Reset</button>
             </div>
           </div>
-
-          <h4 class="panel-title" style="margin-top:24px" data-i18n="settings_hour_height">Stundenhöhe (Wochen- &amp; Tagesansicht)</h4>
-          <p class="panel-desc" data-i18n="settings_hour_height_desc">Wie viel Platz eine Stunde in der Zeitrasteransicht einnimmt</p>
-          <div class="contrast-selector" id="cfg-hour-height" data-setting="hour_height">
-            <button class="contrast-btn" data-val="28"><span class="hour-preview">━━</span><span class="contrast-lbl" data-i18n="hour_compact">Kompakt</span></button>
-            <button class="contrast-btn" data-val="44"><span class="hour-preview">━━━</span><span class="contrast-lbl" data-i18n="hour_normal">Normal</span></button>
-            <button class="contrast-btn" data-val="60"><span class="hour-preview">━━━━</span><span class="contrast-lbl" data-i18n="hour_comfort">Komfort</span></button>
-            <button class="contrast-btn" data-val="80"><span class="hour-preview">━━━━━</span><span class="contrast-lbl" data-i18n="hour_large">Gross</span></button>
-          </div>
         </div>
 
-        <!-- Ansicht: Standardansicht, Wochenstart, vergangene Termine, ausgeblendete Kalender -->
-        <div class="settings-panel" id="settings-panel-view">
-          <h4 class="panel-title" data-i18n="settings_calendar_view">Kalenderansicht</h4>
-          <div class="form-group">
-            <label data-i18n="settings_default_view">Standardansicht</label>
-            <select id="cfg-default-view">
-              <option value="month" data-i18n="view_month">Monat</option>
-              <option value="week" data-i18n="view_week">Woche</option>
-              <option value="day" data-i18n="view_day">Tag</option>
-              <option value="quarter" data-i18n="view_quarter">Quartal</option>
-              <option value="agenda" data-i18n="view_agenda">Termine</option>
-            </select>
-          </div>
-          <div class="form-group">
-            <label data-i18n="settings_week_start">Erster Wochentag</label>
-            <select id="cfg-week-start">
-              <option value="monday" data-i18n="week_start_monday">Montag</option>
-              <option value="sunday" data-i18n="week_start_sunday">Sonntag</option>
-            </select>
-          </div>
-          <div class="form-group">
-            <label class="toggle-label">
-              <input type="checkbox" id="cfg-dim-past" />
-              <span data-i18n="settings_dim_past">Vergangene Termine ausgrauen</span>
-            </label>
-          </div>
-          <div class="form-group">
-            <label data-i18n="settings_default_duration">Standard-Termindauer</label>
-            <select id="cfg-default-duration">
-              <option value="15">15 min</option>
-              <option value="30">30 min</option>
-              <option value="45">45 min</option>
-              <option value="60">1 h</option>
-              <option value="90">1.5 h</option>
-              <option value="120">2 h</option>
-              <option value="240">4 h</option>
-            </select>
-          </div>
-
-          <h4 class="panel-title" style="margin-top:24px" data-i18n="settings_hidden_cals">Ausgeblendete Kalender</h4>
-          <div id="hidden-cals-list"><span style="font-size:13px;color:var(--text-3)" data-i18n="settings_no_hidden_cals">Keine ausgeblendeten Kalender</span></div>
-        </div>
-
-        <!-- Konten (CalDAV, Lokal, iCal, Google) -->
+        <!-- Kalender: einheitliche Tabelle aller Kalender aus allen Quellen -->
         <div class="settings-panel" id="settings-panel-accounts">
           <h4 class="panel-title" data-i18n="settings_nav_calendars">Kalender</h4>
-
-          <div class="accounts-section">
-            <div class="accounts-section-heading" data-i18n="settings_accounts_caldav">CalDAV-Konten</div>
-            <div id="accounts-caldav-list"><span class="accounts-section-empty" data-i18n="settings_no_caldav_accounts">Keine CalDAV-Konten</span></div>
-          </div>
-
-          <div class="accounts-section">
-            <div class="accounts-section-heading" data-i18n="settings_accounts_local">Lokale Kalender</div>
-            <div id="accounts-local-list"><span class="accounts-section-empty" data-i18n="settings_no_local_cals">Keine lokalen Kalender</span></div>
-          </div>
-
-          <div class="accounts-section">
-            <div class="accounts-section-heading" data-i18n="settings_accounts_ical">iCal-Abonnements</div>
-            <div id="accounts-ical-list"><span class="accounts-section-empty" data-i18n="settings_no_ical_subs">Keine Abonnements</span></div>
-          </div>
-
-          <div class="accounts-section">
-            <div class="accounts-section-heading" data-i18n="settings_accounts_google">Google-Konten</div>
-            <div id="google-accounts-list"><span class="accounts-section-empty" data-i18n="settings_no_google_accounts">Keine Google-Konten</span></div>
-          </div>
-
-          <div class="accounts-section">
-            <div class="accounts-section-heading">Home Assistant</div>
-            <div id="accounts-ha-list"><span class="accounts-section-empty">Keine HA-Konten</span></div>
+          <div class="accounts-add-row">
+            <button class="btn btn-secondary btn-sm" id="settings-btn-add-local">+ Lokal</button>
+            <button class="btn btn-secondary btn-sm" id="settings-btn-add-caldav">+ CalDAV</button>
+            <button class="btn btn-secondary btn-sm" id="settings-btn-add-ical">+ iCal</button>
+            <button class="btn btn-secondary btn-sm" id="settings-btn-add-ha">+ Home Assistant</button>
+            <button class="btn btn-secondary btn-sm" id="settings-btn-add-google">+ Google</button>
           </div>
+          <div id="cal-settings-table" style="margin-top:16px;overflow-x:auto"></div>
         </div>
 
         <!-- Benutzerverwaltung -->