feat: FASE 6.5 - Report PDF (WeasyPrint + Kaleido)

Add PDF report generation for Metrologist dashboard with SPC and
measurement reports including SVG charts, capability indices, and
company logo embedding.

New files:
- server/services/report_service.py (Jinja2 + Plotly/Kaleido + WeasyPrint)
- server/routers/reports.py (2 GET endpoints with auth)
- server/templates/reports/ (base, spc, measurement HTML templates)

Modified:
- server/main.py (register reports router)
- client dashboard (download buttons + proxy routes)
- i18n strings IT/EN

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

server/templates/reports/measurement_report.html

@@ -0,0 +1,75 @@
+{% extends "base_report.html" %}
+
+{% block report_title %}Measurement Report{% endblock %}
+
+{% block content %}
+<!-- Recipe info + filters -->
+<div class="info-box">
+  <span class="label">Recipe:</span> {{ recipe.code }} — {{ recipe.name }}
+  {% if filters_desc %}
+  <br>
+  <span class="label">Filters:</span> {{ filters_desc | join(' | ') }}
+  {% endif %}
+</div>
+
+<!-- Summary -->
+<div class="section">
+  <div class="section-title">Summary</div>
+  <div class="summary-grid">
+    <div class="summary-card">
+      <div class="number mono">{{ summary.total }}</div>
+      <div class="label">Total</div>
+    </div>
+    <div class="summary-card pass-bg">
+      <div class="number mono pass">{{ summary.pass_count }}</div>
+      <div class="label">Pass ({{ summary.pass_rate }}%)</div>
+    </div>
+    <div class="summary-card warning-bg">
+      <div class="number mono warning">{{ summary.warning_count }}</div>
+      <div class="label">Warning ({{ summary.warning_rate }}%)</div>
+    </div>
+    <div class="summary-card fail-bg">
+      <div class="number mono fail">{{ summary.fail_count }}</div>
+      <div class="label">Fail ({{ summary.fail_rate }}%)</div>
+    </div>
+  </div>
+</div>
+
+<!-- Measurements Table -->
+<div class="section">
+  <div class="section-title">Measurements ({{ n_measurements }})</div>
+  <table>
+    <thead>
+      <tr>
+        <th>#</th>
+        <th>Measurement Point</th>
+        <th>Value</th>
+        <th>Unit</th>
+        <th>Result</th>
+        <th>Date</th>
+        <th>Operator</th>
+        <th>Lot</th>
+        <th>Serial</th>
+      </tr>
+    </thead>
+    <tbody>
+      {% for row in rows %}
+      <tr class="{% if row.pass_fail == 'fail' %}fail-bg{% elif row.pass_fail == 'warning' %}warning-bg{% endif %}">
+        <td class="mono">{{ row.num }}</td>
+        <td>{{ row.subtask }}</td>
+        <td class="mono">{{ row.value }}</td>
+        <td>{{ row.unit }}</td>
+        <td>
+          <span class="{{ row.pass_fail }}">{{ row.pass_fail | upper }}</span>
+        </td>
+        <td class="mono">{{ row.measured_at }}</td>
+        <td>{{ row.operator }}</td>
+        <td>{{ row.lot_number }}</td>
+        <td>{{ row.serial_number }}</td>
+      </tr>
+      {% endfor %}
+    </tbody>
+  </table>
+</div>
+
+{% endblock %}