fix(tradein/v2): audit #2081 residual — 404 short-circuit, disabled-tab tooltips, stale hex token, ДКП decode

L3: sibling dashboard hooks (analytics/location-coef/placement-history/
sell-time) now short-circuit once restore-by-id confirms 404, instead
of each firing their own doomed request against the same dead
estimate id.
L5: dimmed non-interactive user-menu items (Профиль/Настройки/Помощь)
get a hover title explaining why they're disabled.
L7: TopNav logo subtitle used a stale literal #6f8195 predating the
C1 contrast sweep; now references tokens.muted.
M12: HistoryView's "ДКП-сделки" card gets the same one-time ДКП decode
convention ObjectSummary already uses.

H2/M8/M9/M10/M11 re-verified live/by-code — already correct, no
changes needed (see issue comment). L4 (HistoryView outlier clamp)
and L6 (blueprint-grid background-image) left as follow-ups
(mapper-level change / no contrast payoff respectively).

Refs #2081

tradein-mvp/frontend/src/app/v2/page.tsx

@@ -439,9 +439,24 @@ export default function TradeInV2Page() {
   // Skip the restore fetch once we already hold a fresh result.
   const restored = useEstimate(freshResult === null ? urlId : null);
 
+  // L3 — once the restore-by-id fetch has confirmed the estimate does not
+  // exist (404), `currentEstimateId` below drops to null so the sibling
+  // dashboard hooks (analytics/location-coef/placement-history/sell-time,
+  // all `enabled: estimate_id !== null`) don't each fire their own doomed
+  // request against the same dead id. Hoisted above the sub-hooks (was
+  // computed further down, after they'd already fired on the stale id).
+  const restoreActive = urlId !== null && freshResult === null;
+  const restoreError = restoreActive && restored.isError;
+  const restoreNotFound =
+    restoreError &&
+    restored.error instanceof HTTPError &&
+    restored.error.status === 404;
+
   const estimate: AggregatedEstimate | null =
     freshResult ?? restored.data ?? null;
-  const currentEstimateId = freshResult?.estimate_id ?? urlId;
+  const currentEstimateId = restoreNotFound
+    ? null
+    : (freshResult?.estimate_id ?? urlId);
 
   // Per-user side data, independent of the current estimate. Both fail-soft
   // (retry:false): history feeds the «Предыдущие оценки» overlay (04), quota
@@ -486,13 +501,7 @@ export default function TradeInV2Page() {
   const sellTimeData = sellTime.data ?? null;
 
   // ── Derived state flags ───────────────────────────────────────────────────
-  const restoreActive = urlId !== null && freshResult === null;
   const restoreLoading = restoreActive && restored.isPending;
-  const restoreError = restoreActive && restored.isError;
-  const restoreNotFound =
-    restoreError &&
-    restored.error instanceof HTTPError &&
-    restored.error.status === 404;
 
   const loading = mutation.isPending || restoreLoading;
   const insufficient =

tradein-mvp/frontend/src/components/trade-in/v2/HistoryView.tsx

@@ -175,6 +175,19 @@ export default function HistoryView({
               >
                 {data.dkpHeader.title}
               </div>
+              {/* M12 — расшифровка «ДКП» один раз на секцию, тем же lowercase
+                  hint-стилем что ObjectSummary.rowHint() (fontSize 8/letterSpacing
+                  0.2/muted3), а не uppercase ResultPanel §M8 стилем. */}
+              <div
+                style={{
+                  fontSize: "8px",
+                  letterSpacing: 0.2,
+                  color: tokens.muted3,
+                  marginTop: 2,
+                }}
+              >
+                ДКП · договор купли-продажи
+              </div>
             </div>
             <div
               style={{

tradein-mvp/frontend/src/components/trade-in/v2/TopNav.tsx

@@ -156,7 +156,9 @@ export default function TopNav({
                 fontSize="27"
                 fontWeight="400"
                 letterSpacing="11"
-                fill="#6f8195"
+                // L7 — stale literal from before the C1 contrast sweep darkened
+                // the muted scale; token keeps this logo subtitle in sync.
+                fill={tokens.muted}
               >
                 ОЦЕНКА НЕДВИЖИМОСТИ
               </text>
@@ -370,7 +372,14 @@ export default function TopNav({
                 </div>
               </div>
 
-              <div style={menuItemDisabledStyle} aria-disabled="true">
+              {/* L5 — `title` gives the dimmed/non-interactive item a hover
+                  tooltip explaining WHY it's disabled, instead of a silent dead
+                  row (mirrored on Настройки/Помощь below). */}
+              <div
+                style={menuItemDisabledStyle}
+                aria-disabled="true"
+                title="Раздел «Профиль» скоро появится"
+              >
                 <svg width="15" height="15" viewBox="0 0 15 15" fill="none" aria-hidden="true">
                   <circle
                     cx="7.5"
@@ -412,7 +421,11 @@ export default function TopNav({
                 </span>
               </div>
 
-              <div style={menuItemDisabledStyle} aria-disabled="true">
+              <div
+                style={menuItemDisabledStyle}
+                aria-disabled="true"
+                title="Раздел «Настройки» скоро появится"
+              >
                 <svg width="15" height="15" viewBox="0 0 15 15" fill="none" aria-hidden="true">
                   <circle
                     cx="7.5"
@@ -430,7 +443,11 @@ export default function TopNav({
                 Настройки
               </div>
 
-              <div style={menuItemDisabledStyle} aria-disabled="true">
+              <div
+                style={menuItemDisabledStyle}
+                aria-disabled="true"
+                title="Раздел «Помощь» скоро появится"
+              >
                 <svg width="15" height="15" viewBox="0 0 15 15" fill="none" aria-hidden="true">
                   <circle
                     cx="7.5"