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>

frontend/src/pages/NcrDetailPage.tsx

@@ -35,6 +35,7 @@ import { RichTextView } from "../components/RichTextView";
 import { StageChip } from "../components/StageChip";
 import { StageStepper } from "../components/StageStepper";
 import { useToast } from "../components/Toast";
+import { CapaSection } from "./CapaSection";
 import {
   CostingForm,
   InitialDispositionForm,
@@ -262,6 +263,10 @@ function DetailBody({ ncr }: { ncr: NcrDetail }) {
         )}
       </SectionCard>
 
+      <SectionCard title="Corrective & Preventive Action (API Q1)">
+        <CapaSection ncr={ncr} />
+      </SectionCard>
+
       <SectionCard title="Costing">
         <Grid container spacing={2}>
           <FieldRow label="Labor">{money(ncr.labor_cost)}</FieldRow>