style(workflows): stack the lane pipeline and skill usage panels

Both panels carry wide tables that were fighting for half a row on lg
screens. Each gets its own full-width row instead.

client/src/pages/Workflows.tsx

@@ -205,21 +205,20 @@ export function Workflows() {
       {/* Stats Row */}
       <WorkflowStats stats={data.stats} />
 
-      {/* Section 1 + 2: this dashboard's own pipelines, and what drives them */}
-      <div className="grid grid-cols-1 lg:grid-cols-2 gap-6">
-        <Section number={1} title={t("lanes.title")} subtitle={t("lanes.subtitle")} infoKey="lanes">
-          <LanePipelinePanel />
-        </Section>
+      {/* Section 1: this dashboard's own pipelines */}
+      <Section number={1} title={t("lanes.title")} subtitle={t("lanes.subtitle")} infoKey="lanes">
+        <LanePipelinePanel />
+      </Section>
 
-        <Section
-          number={2}
-          title={t("skillUsage.title")}
-          subtitle={t("skillUsage.subtitle")}
-          infoKey="skillUsage"
-        >
-          <SkillUsagePanel statusFilter={statusFilter} />
-        </Section>
-      </div>
+      {/* Section 2: what drives those pipelines */}
+      <Section
+        number={2}
+        title={t("skillUsage.title")}
+        subtitle={t("skillUsage.subtitle")}
+        infoKey="skillUsage"
+      >
+        <SkillUsagePanel statusFilter={statusFilter} />
+      </Section>
 
       {/* Workflow-tool runs (issue #167) - fleets ingested from on-disk journals */}
       <div className="card p-4 space-y-3">