Implement modular report system with 6 report types and composer UI

Refactors the Berichte section from a single hardcoded Jahresbericht into
a modular report-building system. Jahresbericht now uses PDFGenerator for
corporate identity (logo, colors, headers/footers, cover page). 8 reusable
section templates can be freely combined. 6 predefined report templates
(Jahres-, Destinatär-, Grundstücks-, Finanz-, Förder-, Pachtbericht) with
HTML preview and PDF export. New Bericht-Baukasten UI lets users compose
custom reports from individual sections.

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

app/templates/berichte/sektionen/verpachtungen.html

@@ -0,0 +1,88 @@
+<!-- Sektion: Pachtbericht -->
+<div class="section">
+  <h2>Pachtbericht{% if jahr %} {{ jahr }}{% endif %}</h2>
+
+  {% if pacht_statistik %}
+  <div class="stats-grid">
+    <div class="stat-card">
+      <div class="value">{{ pacht_statistik.aktive_vertraege }}</div>
+      <div class="label">Aktive Pachtvertr&auml;ge</div>
+    </div>
+    <div class="stat-card">
+      <div class="value">&#8364;{{ pacht_statistik.total_pachtzins|floatformat:2 }}</div>
+      <div class="label">Gesamtpachtzins p.a.</div>
+    </div>
+    <div class="stat-card">
+      <div class="value">{{ pacht_statistik.total_flaeche|floatformat:0 }} qm</div>
+      <div class="label">Verpachtete Fl&auml;che</div>
+    </div>
+    <div class="stat-card">
+      <div class="value">{{ pacht_statistik.auslaufend_12m }}</div>
+      <div class="label">Laufen in 12 Mon. aus</div>
+    </div>
+  </div>
+  {% endif %}
+
+  {% if pacht_auslaufend %}
+  <h3>Auslaufende Vertr&auml;ge (n&auml;chste 12 Monate)</h3>
+  <table>
+    <thead>
+      <tr>
+        <th>L&auml;nderei</th>
+        <th>P&auml;chter</th>
+        <th>Pachtende</th>
+        <th>Pachtzins</th>
+      </tr>
+    </thead>
+    <tbody>
+      {% for v in pacht_auslaufend %}
+      <tr>
+        <td>{{ v.land }}</td>
+        <td>{{ v.paechter.get_full_name }}</td>
+        <td>{{ v.pachtende|date:"d.m.Y" }}</td>
+        <td class="amount">&#8364;{{ v.pachtzins_pauschal|floatformat:2 }}</td>
+      </tr>
+      {% endfor %}
+    </tbody>
+  </table>
+  {% endif %}
+
+  {% if verpachtungen %}
+  <h3>Alle Verpachtungen</h3>
+  <table>
+    <thead>
+      <tr>
+        <th>L&auml;nderei</th>
+        <th>P&auml;chter</th>
+        <th>Fl&auml;che</th>
+        <th>Pachtzins</th>
+        <th>Beginn</th>
+        <th>Ende</th>
+        <th>Status</th>
+      </tr>
+    </thead>
+    <tbody>
+      {% for v in verpachtungen %}
+      <tr>
+        <td>{{ v.land }}</td>
+        <td>{{ v.paechter.get_full_name }}</td>
+        <td class="amount">{{ v.verpachtete_flaeche|floatformat:0 }} qm</td>
+        <td class="amount">&#8364;{{ v.pachtzins_pauschal|floatformat:2 }}</td>
+        <td>{{ v.pachtbeginn|date:"d.m.Y" }}</td>
+        <td>{% if v.pachtende %}{{ v.pachtende|date:"d.m.Y" }}{% else %}unbefristet{% endif %}</td>
+        <td>
+          <span class="status-badge status-{{ v.status }}">{{ v.get_status_display }}</span>
+        </td>
+      </tr>
+      {% endfor %}
+    </tbody>
+    <tfoot>
+      <tr style="font-weight: bold; background: #f0f7f4;">
+        <td colspan="3">Gesamtpachtzins</td>
+        <td class="amount">&#8364;{{ total_pachtzins|floatformat:2 }}</td>
+        <td colspan="3"></td>
+      </tr>
+    </tfoot>
+  </table>
+  {% endif %}
+</div>