feat(translate): add run preflight and focus execution UX

frontend/src/lib/components/translate/RunTabContent.svelte

@@ -8,9 +8,9 @@
 <!-- @RELATION DEPENDS_ON -> [TranslationRunResult] -->
 <!-- @RELATION DEPENDS_ON -> [TranslateMetricsRoutesModule] -->
 <!-- @RELATION BINDS_TO -> [translationRunStore] -->
-<!-- @UX_STATE Idle — no run active, run cards visible -->
-<!-- @UX_STATE Running — TranslationRunProgress bar visible, cards show active state -->
-<!-- @UX_STATE Completed — run history list with expandable details, summary metrics bar -->
+<!-- @UX_STATE Idle — run estimate and launch choices are the only primary content. -->
+<!-- @UX_STATE Running — TranslationRunProgress is the sole primary content; setup and history are hidden. -->
+<!-- @UX_STATE Completed — result remains primary; history and cumulative metrics are collapsed secondary content. -->
 <!-- @UX_STATE Error — error banner above run history -->
 <!-- @UX_FEEDBACK Toast on status change / run error / run complete -->
 <!-- @UX_FEEDBACK BulkReplace modal button in recent runs header -->
@@ -61,6 +61,7 @@
   let metricsLoading = $state(false);
   let metricsError = $state(null);
   let wasRunActive = false;
+  let secondaryDetailsOpen = $state(false);
 
   // Confirmation dialog state
   let showConfirmDialog = $state(false);
@@ -124,6 +125,7 @@
   });
 
   $effect(() => {
+    if (isRunActive) secondaryDetailsOpen = false;
     if (wasRunActive && !isRunActive) loadJobMetrics();
     wasRunActive = isRunActive;
   });
@@ -199,12 +201,13 @@
   <!-- Status display + transition -->
   <div class="flex items-center gap-3 mb-4 p-3 bg-surface-muted rounded-lg">
     <span class="text-sm text-text-muted">{_t.translate?.config?.status}:</span>
-    <span class="inline-flex items-center px-2.5 py-0.5 rounded-full text-xs font-medium {statusClass}">
-      {getJobStatusLabel(status)}
+    <span class="inline-flex items-center px-2.5 py-0.5 rounded-full text-xs font-medium {isRunActive ? 'bg-primary-light text-primary' : statusClass}">
+      {isRunActive ? (_t.translate?.config?.running || 'Running') : getJobStatusLabel(status)}
     </span>
   </div>
 
   <div class="space-y-4">
+    {#if !isRunActive}
     <!-- Run evidence: real source scope, local Lingua distribution, and cost before execution -->
     <div class="border border-border rounded-lg bg-surface-card p-4" aria-busy={preflightLoading}>
       <div class="flex flex-wrap items-center justify-between gap-3">
@@ -303,6 +306,7 @@
         </div>
       </div>
     </div>
+    {/if}
 
     {#if runError}
       <div class="bg-destructive-light border border-destructive-light rounded-lg p-3">
@@ -319,6 +323,24 @@
       />
     {/if}
 
+    {#if !isRunActive}
+    <!-- Secondary context: it must not compete with the next launch or an active run. -->
+    <div class="rounded-lg border border-border bg-surface-card">
+      <button
+        type="button"
+        onclick={() => secondaryDetailsOpen = !secondaryDetailsOpen}
+        aria-expanded={secondaryDetailsOpen}
+        class="flex w-full items-center justify-between gap-3 px-4 py-3 text-left text-sm font-medium text-text hover:bg-surface-muted"
+      >
+        <span>{_t.translate?.run?.secondary_details || 'History and job metrics'}</span>
+        <span class="text-xs font-normal text-text-muted">
+          {secondaryDetailsOpen
+            ? (_t.translate?.run?.hide_details || 'Hide details')
+            : (_t.translate?.run?.show_details || 'Show details')}
+        </span>
+      </button>
+      {#if secondaryDetailsOpen}
+        <div class="border-t border-border p-4 space-y-4">
     <!-- Summary metrics bar -->
     {#if jobMetrics}
       <div class="bg-surface-card border border-border rounded-lg p-4">
@@ -401,7 +423,7 @@
     {/if}
 
     {#if completedRuns.length > 0}
-      <div class="mt-4">
+      <div>
         <div class="flex items-center justify-between mb-2">
           <h4 class="text-sm font-medium text-text">{_t.translate?.config?.recent_runs}</h4>
           <button
@@ -489,6 +511,10 @@
           {/if}
         </div>
       </div>
+    {/if}
+        </div>
+      {/if}
+    </div>
     {/if}
   </div>
 

frontend/src/lib/i18n/locales/en/translate.json

@@ -527,6 +527,7 @@
     "preflight_rows_sec": "rows/s",
     "preflight_languages": "Source language distribution",
     "preflight_lingua_slow": "Lingua exceeded the performance threshold. The run will continue without local language detection.",
+    "secondary_details": "History and job metrics",
     "loading": "Loading run status...",
     "loading_result": "Loading result...",
     "result_title": "Run Result",

frontend/src/lib/i18n/locales/ru/translate.json

@@ -528,6 +528,7 @@
     "preflight_rows_sec": "строк/с",
     "preflight_languages": "Распределение исходных языков",
     "preflight_lingua_slow": "Lingua превысила порог производительности. Перевод продолжится без локального определения языка.",
+    "secondary_details": "История и метрики задания",
     "loading": "Загрузка статуса запуска...",
     "loading_result": "Загрузка результата...",
     "result_title": "Результат запуска",