Add API Q1 CAPA: root cause, corrective action gate, effectiveness verification

Implements tester feedback against API Q1 §5.9.1.2 / §6.4.2:

- Root Cause field + 6M Root Cause Category lookup (Man/Machine/Method/
  Material/Measurement/Environment), separate from Deviation Detail/Category
- "Corrective Action Required?" Yes/No gate on every NCR with a required
  justification
- Corrective action plan with owner + due date; owner is notified by email
- Effectiveness verification (result, notes, server-stamped verifier/date)
  required before an NCR can close when corrective action is required —
  costing returns 409 listing the missing pieces
- Recurring-issue flag with bidirectional NCR-to-NCR links; prior NCRs show
  a warning when later NCRs reference them
- Dashboard metrics: % root cause completed, % CAPA verified effective,
  avg CAPA close time, overdue CAPA count, NCRs by root cause category
- CAPA section in the NCR detail UI, printable PDF, CSV export, and the
  vw_ncr_full Power BI view; admin list manager for root cause categories
- Migrations 0003 (schema + seeded 6M lookup) and 0004 (view refresh);
  demo seed data exercises every metric

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

backend/app/templates/ncr_pdf.html

@@ -134,6 +134,61 @@
   <div class="notes">{{ ncr.inspection_notes }}</div>
 {% endif %}
 
+<h2>Corrective &amp; Preventive Action (API Q1)</h2>
+<table class="fields">
+  <tr>
+    <td class="lbl">Root Cause Category</td>
+    <td>{{ ncr.root_cause_category.name if ncr.root_cause_category else "—" }}</td>
+    <td class="lbl">Recurring Issue</td>
+    <td>
+      {% if ncr.is_recurring %}Yes{% if related_ncr_numbers %} —
+        {{ related_ncr_numbers | join(", ") }}{% endif %}
+      {% else %}No{% endif %}
+    </td>
+  </tr>
+  <tr>
+    <td class="lbl">Corrective Action Required</td>
+    <td>
+      {% if ncr.corrective_action_required is none %}<span class="pending">Not answered</span>
+      {% elif ncr.corrective_action_required %}Yes{% else %}No{% endif %}
+    </td>
+    <td class="lbl">Justification</td>
+    <td>{{ ncr.corrective_action_justification or "—" }}</td>
+  </tr>
+  <tr>
+    <td class="lbl">Action Owner</td>
+    <td>{{ ncr.corrective_action_owner.display_name if ncr.corrective_action_owner else "—" }}</td>
+    <td class="lbl">Due Date</td>
+    <td>{{ ncr.corrective_action_due_date.strftime("%Y-%m-%d") if ncr.corrective_action_due_date else "—" }}</td>
+  </tr>
+  <tr>
+    <td class="lbl">Effectiveness</td>
+    <td>
+      {% if ncr.effectiveness_result == "effective" %}Verified Effective
+      {% elif ncr.effectiveness_result == "not_effective" %}Not Effective
+      {% else %}<span class="pending">Pending verification</span>{% endif %}
+    </td>
+    <td class="lbl">Verified By / At</td>
+    <td>
+      {% if ncr.effectiveness_verified_by %}
+        {{ ncr.effectiveness_verified_by.display_name }} —
+        {{ ncr.effectiveness_verified_at.strftime("%Y-%m-%d %H:%M") }} UTC
+      {% else %}—{% endif %}
+    </td>
+  </tr>
+</table>
+{% if ncr.root_cause %}
+  <div class="notes"><strong>Root Cause:</strong> {{ ncr.root_cause }}</div>
+{% else %}
+  <div class="notes pending">No root cause recorded.</div>
+{% endif %}
+{% if ncr.corrective_action_plan %}
+  <div class="notes"><strong>Corrective Action Plan:</strong> {{ ncr.corrective_action_plan }}</div>
+{% endif %}
+{% if ncr.effectiveness_notes %}
+  <div class="notes"><strong>Verification Notes:</strong> {{ ncr.effectiveness_notes }}</div>
+{% endif %}
+
 <h2>Costing</h2>
 <table class="fields costs">
   <tr>