M8: GUI polish, n8n workflow-3 fixes, RAGcore retrieval root-cause and fix

GUI: dashboard Attention Queue presents a curated severity mix instead of pure
severity-sort (grouped Now/Today/Later headers); Today's Movements seed data
curated so a fresh reset shows a credible day (2+ departures, 2+ returns), with
a new seed-integrity test; About Demo restructured into a compact grid with
progressive disclosure for technical sections; Duplicate Merge shows match/conflict
counts, hides matching fields by default, and previews the final merged record
before confirmation.

Repo hygiene: removed a stray empty `backend;C` directory and an untracked 31MB
zip export; `.gitignore` now excludes future archive exports.

n8n: fixed invalid JSON (a missing `},` between two node objects) in the committed
`fleet-ops-vehicle-return.json` -- the file could not be parsed. Live-validated
workflow 3 (RAGcore Procedure Sync): found and fixed a real defect (three body
parameters had a stray trailing `}}`) and a missing Error Workflow wiring, both
via the safe `n8n import:workflow` CLI path; exported the corrected, still-
inactive workflow as the new source of truth and updated MANIFEST.md/check_drift.py.
Publishing it (starts real daily unattended runs) remains a separate decision.

RAGcore: root-caused and fixed (live, approved) the "zero retrieval candidates"
bug -- a filesystem permission bug (`embedding_profiles.json` unreadable by the
app's own runtime user) that broke every retrieval call before it reached Qdrant.
Every other suspect (grants, scope resolution, Qdrant filters, embeddings) was
verified healthy first. Found a second, deeper gap: the reranker adapter calls
an Ollama HTTP route that does not exist on the deployed Ollama version, so
`/v1/answers` still returns `not_answerable`. `KNOWLEDGE_PROVIDER` stays `demo`
until that is resolved on the RAGcore side. Evidence-based MCP Hub integration
status (real tool-call audit history, not just a boolean flag) replaces the old
`configured`/`not_configured` guess. Full findings in
`docs/final-integrations/current-state-audit.md`.

Backend: 172 tests passing, ruff clean, mypy clean (50 files). Frontend: tsc
clean, production build clean.

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

frontend/src/pages/DataQualityIssueDetail.tsx

@@ -128,6 +128,7 @@ function DuplicateCustomerPanel({ issue, onResolved }: { issue: IssueDetail; onR
   const [error, setError] = useState<ApiErrorInfo | null>(null);
   const [submitting, setSubmitting] = useState(false);
   const [confirming, setConfirming] = useState(false);
+  const [showMatching, setShowMatching] = useState(false);
 
   if (!issue.entity_snapshot || !issue.related_snapshots[0]) {
     return <p className="error">{t("detail.duplicateCustomer.bothMissing")}</p>;
@@ -137,6 +138,9 @@ function DuplicateCustomerPanel({ issue, onResolved }: { issue: IssueDetail; onR
 
   const survivor = survivorRef === a.public_ref ? a : b;
   const loser = survivorRef === a.public_ref ? b : a;
+  const conflictingFields = MERGE_FIELDS.filter((field) => String(a[field] ?? "") !== String(b[field] ?? ""));
+  const matchingFields = MERGE_FIELDS.filter((field) => !conflictingFields.includes(field));
+  const visibleFields = showMatching ? MERGE_FIELDS : conflictingFields;
 
   async function handleMerge() {
     setError(null);
@@ -174,6 +178,10 @@ function DuplicateCustomerPanel({ issue, onResolved }: { issue: IssueDetail; onR
       <SectionHeading headingId="compare-heading" title={t("detail.duplicateCustomer.heading")} description={t("detail.duplicateCustomer.description")} />
       <ApiErrorNotice error={error} />
 
+      <p className="merge-summary-counts">
+        {t("detail.duplicateCustomer.summaryCounts", { matchCount: matchingFields.length, conflictCount: conflictingFields.length })}
+      </p>
+
       <fieldset className="choice-fieldset">
         <legend>{t("detail.duplicateCustomer.keepAsSurvivor")}</legend>
         <label className={`choice-card ${survivorRef === a.public_ref ? "is-selected" : ""}`}>
@@ -205,7 +213,7 @@ function DuplicateCustomerPanel({ issue, onResolved }: { issue: IssueDetail; onR
           </tr>
         </thead>
         <tbody>
-          {MERGE_FIELDS.map((field) => {
+          {visibleFields.map((field) => {
             const valueA = a[field] ? String(a[field]) : "—";
             const valueB = b[field] ? String(b[field]) : "—";
             const differ = valueA !== valueB;
@@ -248,10 +256,33 @@ function DuplicateCustomerPanel({ issue, onResolved }: { issue: IssueDetail; onR
         </tbody>
       </table>
 
+      {matchingFields.length > 0 && (
+        <button type="button" className="button button-tertiary toggle-matching-fields" onClick={() => setShowMatching((v) => !v)}>
+          {showMatching ? t("detail.duplicateCustomer.hideMatchingFields") : t("detail.duplicateCustomer.showMatchingFields")}
+        </button>
+      )}
+
       <p className="merge-preview">
         {t("detail.duplicateCustomer.mergePreview", { loser: loser.public_ref, survivor: survivor.public_ref })}
       </p>
 
+      <div className="merge-record-preview">
+        <p className="merge-record-preview-title">{t("detail.duplicateCustomer.previewTitle", { ref: survivor.public_ref })}</p>
+        <dl>
+          {MERGE_FIELDS.map((field) => {
+            const choice = fieldChoices[field];
+            const chosenSide = choice === "a" ? a : choice === "b" ? b : survivor;
+            const value = (chosenSide[field] ? String(chosenSide[field]) : survivor[field] ? String(survivor[field]) : "—");
+            return (
+              <div key={field}>
+                <dt>{t(`detail.duplicateCustomer.fields.${field}`)}</dt>
+                <dd>{value || "—"}</dd>
+              </div>
+            );
+          })}
+        </dl>
+      </div>
+
       {!confirming && (
         <button type="button" className="button button-primary" onClick={() => setConfirming(true)}>
           {t("detail.duplicateCustomer.mergeInto", { ref: survivor.public_ref })}