feat(forecast): show compute date / horizons / schema in Section 6 footer

Surface report.meta provenance as a compact muted caption above the advisory
disclaimer: «Прогноз рассчитан: <дата> · горизонты N / M мес · схема X». The
freshness date sources from the run's persist time (envelope created_at, always
set) with meta.generated_at as fallback — the deterministic assembler leaves
generated_at null, but created_at is the real compute timestamp. Until now this
provenance lived only in exports; horizons appeared only via the chart axis.

New ForecastMetaLine.tsx: three independently-guarded segments (RU long date
with optional non-midnight time, horizons, most-muted schema); graceful null
when meta empty / 202-pending. Advisory disclaimer stays last.

Part of #958.

frontend/src/components/site-finder/analysis/ForecastMetaLine.tsx

@@ -0,0 +1,146 @@
+"use client";
+
+/**
+ * ForecastMetaLine — compact freshness / traceability footer for Section 6 (§22).
+ *
+ * Surfaces the report `meta` provenance that, until now, lived only in the
+ * exports («Сформировано» row): WHEN the forecast was computed, over WHICH
+ * horizons, and the schema version. For a forecasting tool «прогноз рассчитан
+ * <дата>» is a trust/staleness signal — without it the horizons appear only
+ * implicitly via the chart axis and the compute date is invisible.
+ *
+ * Three independently-guarded segments joined by a middot, caption typography,
+ * muted tokens (schema is the MOST muted — traceability, not headline):
+ *
+ *   Прогноз рассчитан: 7 июня 2026 · горизонты 6 / 12 / 18 / 24 мес · схема 1.0
+ *
+ * Date source: the run's persist time (`runCreatedAt` — the forecast envelope's
+ * `created_at`, always set for a persisted run) is preferred; `meta.generated_at`
+ * is the fallback. The PURE assembler / orchestrator deliberately do NOT stamp
+ * `generated_at` (determinism), so it is frequently null in real runs — but the
+ * persisted run always carries `created_at`, which is the real «когда рассчитан».
+ *
+ * GRACEFUL: renders null when every segment is empty (e.g. 202-pending or a thin
+ * report). When neither date source resolves, only that segment is skipped while
+ * horizons + schema still render. An invalid/unparseable date is treated as
+ * missing. A date-only ISO string («2026-06-03») renders date-only; a datetime
+ * with a meaningful (non-midnight) time appends «, ЧЧ:ММ» — a real run timestamp
+ * carries a genuine time, so it shows «7 июня 2026, 14:20» (precise compute time).
+ */
+
+import type { ReportMeta } from "@/types/forecast";
+
+/** «6 / 12 / 18 / 24 мес» — horizons joined; "" when the list is empty. */
+function formatHorizons(horizons: number[]): string {
+  if (horizons.length === 0) return "";
+  return `${horizons.join(" / ")} мес`;
+}
+
+/**
+ * «7 июня 2026» (date-only) or «7 июня 2026, 10:30» (meaningful time) — RU long
+ * date from an ISO 8601 string. Returns "" for null/empty/unparseable input.
+ *
+ * A bare date («2026-06-03») parses to local midnight, so a 00:00 time is treated
+ * as «no time» to avoid a misleading «, 00:00». A datetime carrying a real time
+ * (and an explicit time component in the source string) appends «, ЧЧ:ММ».
+ */
+function formatComputedAt(computedAt: string | null): string {
+  if (computedAt == null || computedAt.trim() === "") return "";
+  const ts = Date.parse(computedAt);
+  if (Number.isNaN(ts)) return "";
+
+  const date = new Date(ts);
+  const datePart = date.toLocaleDateString("ru", {
+    day: "numeric",
+    month: "long",
+    year: "numeric",
+  });
+
+  const hasTimeComponent = computedAt.includes("T");
+  const isMidnight = date.getHours() === 0 && date.getMinutes() === 0;
+  if (!hasTimeComponent || isMidnight) return datePart;
+
+  const timePart = date.toLocaleTimeString("ru", {
+    hour: "2-digit",
+    minute: "2-digit",
+  });
+  return `${datePart}, ${timePart}`;
+}
+
+const SEP_STYLE: React.CSSProperties = {
+  color: "var(--fg-tertiary)",
+  // hair spaces around the middot for RU typographic breathing room.
+  padding: "0 2px",
+};
+
+export function ForecastMetaLine({
+  meta,
+  runCreatedAt,
+}: {
+  meta: ReportMeta;
+  /**
+   * The forecast envelope's `created_at` (the run's persist time) — the real
+   * «когда рассчитан» signal, always set for a persisted run. Preferred over the
+   * frequently-null `meta.generated_at`.
+   */
+  runCreatedAt?: string | null;
+}) {
+  // Run persist time wins; the (often null) deterministic meta stamp is fallback.
+  const computedAt = formatComputedAt(runCreatedAt ?? meta.generated_at);
+  const horizons = formatHorizons(meta.horizons);
+  const schemaVersion = meta.schema_version?.trim() ?? "";
+
+  const segments: React.ReactNode[] = [];
+  if (computedAt) {
+    segments.push(
+      <span key="generated" style={{ color: "var(--fg-secondary)" }}>
+        Прогноз рассчитан: {computedAt}
+      </span>,
+    );
+  }
+  if (horizons) {
+    segments.push(
+      <span key="horizons" style={{ color: "var(--fg-secondary)" }}>
+        горизонты {horizons}
+      </span>,
+    );
+  }
+  if (schemaVersion) {
+    segments.push(
+      <span key="schema" style={{ color: "var(--fg-tertiary)" }}>
+        схема {schemaVersion}
+      </span>,
+    );
+  }
+
+  if (segments.length === 0) return null;
+
+  return (
+    <p
+      style={{
+        margin: 0,
+        display: "flex",
+        flexWrap: "wrap",
+        alignItems: "baseline",
+        rowGap: 4,
+        fontSize: 12,
+        lineHeight: 1.5,
+        color: "var(--fg-secondary)",
+      }}
+    >
+      {segments.map((segment, i) => (
+        <span
+          key={i}
+          style={{ display: "inline-flex", alignItems: "baseline" }}
+        >
+          {i > 0 && (
+            <span aria-hidden style={SEP_STYLE}>
+              ·
+            </span>
+          )}
+          {segment}
+        </span>
+      ))}
+    </p>
+  );
+}

frontend/src/components/site-finder/analysis/Section6Forecast.tsx

@@ -35,6 +35,7 @@ import { ForecastConfidenceBlock } from "./ForecastConfidenceBlock";
 import { ForecastProductTzBlock } from "./ForecastProductTzBlock";
 import { ForecastScoringBlock } from "./ForecastScoringBlock";
 import { ForecastFutureSupplyBlock } from "./ForecastFutureSupplyBlock";
+import { ForecastMetaLine } from "./ForecastMetaLine";
 import { ForecastExportButtons } from "./ForecastExportButtons";
 import {
   CONFIDENCE_RU,
@@ -161,6 +162,7 @@ export function Section6Forecast({ cad, selectedHorizon }: Props) {
     <ForecastReady
       cad={cad}
       report={data.report}
+      runCreatedAt={data.created_at}
       selectedHorizon={selectedHorizon}
     />
   );
@@ -171,10 +173,13 @@ export function Section6Forecast({ cad, selectedHorizon }: Props) {
 function ForecastReady({
   cad,
   report,
+  runCreatedAt,
   selectedHorizon,
 }: {
   cad: string;
   report: ForecastReport;
+  /** Envelope `created_at` — the run's persist time, the real «когда рассчитан». */
+  runCreatedAt?: string | null;
   selectedHorizon?: number;
 }) {
   const exec = report.exec_summary;
@@ -394,19 +399,30 @@ function ForecastReady({
           </SubBlock>
         )}
 
-        {/* Advisory disclaimer */}
-        <p
+        {/* Freshness / traceability: когда рассчитан + горизонты + версия схемы */}
+        <div
           style={{
-            margin: 0,
-            fontSize: 12,
-            lineHeight: 1.5,
-            color: "var(--fg-tertiary)",
+            display: "flex",
+            flexDirection: "column",
+            gap: 6,
             paddingTop: 12,
             borderTop: "1px solid var(--border-soft)",
           }}
         >
-          {ADVISORY_DISCLAIMER}
-        </p>
+          <ForecastMetaLine meta={report.meta} runCreatedAt={runCreatedAt} />
+
+          {/* Advisory disclaimer (всегда последним) */}
+          <p
+            style={{
+              margin: 0,
+              fontSize: 12,
+              lineHeight: 1.5,
+              color: "var(--fg-tertiary)",
+            }}
+          >
+            {ADVISORY_DISCLAIMER}
+          </p>
+        </div>
       </div>
     </section>
   );