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/Dashboard.tsx

@@ -75,6 +75,17 @@ export function Dashboard() {
     return matchesSeverity && haystack.includes(query.toLowerCase());
   }) ?? [], [data, query, severity, t]);
 
+  const isUnfiltered = severity === "all" && query === "";
+  const attentionTiers = useMemo(() => {
+    if (!isUnfiltered) return [{ key: "all", labelKey: "", items: attention.slice(0, 6) }];
+    const bySeverity = (level: string) => attention.filter((item) => item.severity === level);
+    return [
+      { key: "high", labelKey: "attention.tierNow", items: bySeverity("high") },
+      { key: "medium", labelKey: "attention.tierToday", items: bySeverity("medium") },
+      { key: "low", labelKey: "attention.tierLater", items: bySeverity("low") },
+    ].filter((tier) => tier.items.length > 0);
+  }, [attention, isUnfiltered]);
+
   if (error) return <ErrorState message={error} />;
   if (!data) return <LoadingState label={t("common:status.loading")} />;
 
@@ -129,32 +140,39 @@ export function Dashboard() {
             <label><span className="visually-hidden">{t("attention.severityAriaLabel")}</span><select value={severity} onChange={(event) => setSeverity(event.target.value)}><option value="all">{t("attention.severityAll")}</option><option value="high">{t("attention.severityHigh")}</option><option value="medium">{t("attention.severityMedium")}</option><option value="low">{t("attention.severityLow")}</option></select></label>
           </div>
           {attention.length === 0 ? <p className="quiet-empty"><Icon name="check" /> {t("attention.empty")}</p> : (
-            <ul className="attention-list">
-              {attention.slice(0, 6).map((item, index) => {
-                const href = item.issue_ref && canSeeQuality
-                  ? `/data-quality/${item.issue_ref}`
-                  : item.link_type === "vehicle"
-                    ? `/vehicles/${item.link_ref}`
-                    : null;
-                const title = attentionItemTitle(t, item);
-                return (
-                  <li key={`${item.link_ref}-${index}`} className={href ? "row-clickable" : ""}>
-                    <SeverityBadge severity={item.severity} />
-                    <div className="queue-copy">
-                      <p className="attention-title">{title}</p>
-                      <p className="attention-detail">{item.detail}</p>
-                    </div>
-                    <span className="queue-ref">{item.link_ref}</span>
-                    <Icon name="chevron" className="row-chevron" />
-                    {href && (
-                      <Link className="row-link" to={href} aria-label={t("attention.openRecord", { title })}>
-                        <span className="visually-hidden">{title}</span>
-                      </Link>
-                    )}
-                  </li>
-                );
-              })}
-            </ul>
+            <>
+              {attentionTiers.map((tier) => (
+                <div key={tier.key} className="attention-tier">
+                  {attentionTiers.length > 1 && <p className="attention-tier-label">{t(tier.labelKey)}</p>}
+                  <ul className="attention-list">
+                    {tier.items.map((item, index) => {
+                      const href = item.issue_ref && canSeeQuality
+                        ? `/data-quality/${item.issue_ref}`
+                        : item.link_type === "vehicle"
+                          ? `/vehicles/${item.link_ref}`
+                          : null;
+                      const title = attentionItemTitle(t, item);
+                      return (
+                        <li key={`${item.link_ref}-${index}`} className={href ? "row-clickable" : ""}>
+                          <SeverityBadge severity={item.severity} />
+                          <div className="queue-copy">
+                            <p className="attention-title">{title}</p>
+                            <p className="attention-detail">{item.detail}</p>
+                          </div>
+                          <span className="queue-ref">{item.link_ref}</span>
+                          <Icon name="chevron" className="row-chevron" />
+                          {href && (
+                            <Link className="row-link" to={href} aria-label={t("attention.openRecord", { title })}>
+                              <span className="visually-hidden">{title}</span>
+                            </Link>
+                          )}
+                        </li>
+                      );
+                    })}
+                  </ul>
+                </div>
+              ))}
+            </>
           )}
         </section>