feat(evaluation): dataset card and run detail components

`DatasetCard` lists stored datasets and owns the upload dialog, the start
button and the delete confirmation. Starting is gated on `runActive`,
passed down from the run list — runs are serialised server-side, so the
button should be disabled rather than reliably 409.

`RunDetail` renders one run: header, error, indexing panel, quality panel
and the per-question table. It polls only while `isActiveStatus(status)`,
so a finished run stops refetching instead of polling a row that can no
longer change.

Both are self-contained: the page that composes them lands next.

Author: EnjoyBacon7

ui/src/pages/admin/evaluation/dataset-card.tsx

@@ -0,0 +1,222 @@
+import { useState } from "react";
+import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
+import { toast } from "sonner";
+import { Play, Trash2, Upload } from "lucide-react";
+import {
+  createEvalDataset,
+  deleteEvalDataset,
+  listEvalDatasets,
+  startEvalRun,
+} from "@/lib/api/evaluation";
+import { ConfirmDialog } from "@/components/shared/confirm-dialog";
+import { Button } from "@/components/ui/button";
+import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "@/components/ui/card";
+import {
+  Dialog,
+  DialogContent,
+  DialogDescription,
+  DialogFooter,
+  DialogHeader,
+  DialogTitle,
+} from "@/components/ui/dialog";
+import { Input } from "@/components/ui/input";
+import { Label } from "@/components/ui/label";
+import { Skeleton } from "@/components/ui/skeleton";
+import { Table, TableBody, TableCell, TableHead, TableHeader, TableRow } from "@/components/ui/table";
+
+const CSV_HINT = "question,expected_answer,expected_file_ids";
+
+export function DatasetCard({ runActive }: { runActive: boolean }) {
+  const queryClient = useQueryClient();
+  const [uploadOpen, setUploadOpen] = useState(false);
+
+  const { data, isLoading } = useQuery({ queryKey: ["eval-datasets"], queryFn: listEvalDatasets });
+
+  const startMut = useMutation({
+    mutationFn: (datasetId: string) => startEvalRun(datasetId),
+    onSuccess: () => {
+      toast.success("Evaluation run queued");
+      queryClient.invalidateQueries({ queryKey: ["eval-runs"] });
+    },
+    onError: (e) => toast.error((e as Error).message),
+  });
+
+  const deleteMut = useMutation({
+    mutationFn: (id: string) => deleteEvalDataset(id),
+    onSuccess: () => {
+      toast.success("Dataset deleted");
+      queryClient.invalidateQueries({ queryKey: ["eval-datasets"] });
+    },
+    onError: (e) => toast.error((e as Error).message),
+  });
+
+  const datasets = data ?? [];
+
+  return (
+    <Card>
+      <CardHeader className="flex flex-row items-start justify-between">
+        <div>
+          <CardTitle>Datasets</CardTitle>
+          <CardDescription>
+            A corpus to index plus a CSV test set (<code>{CSV_HINT}</code>).
+          </CardDescription>
+        </div>
+        <Button size="sm" onClick={() => setUploadOpen(true)}>
+          <Upload className="mr-2 h-4 w-4" />
+          New dataset
+        </Button>
+      </CardHeader>
+      <CardContent>
+        {isLoading ? (
+          <Skeleton className="h-24" />
+        ) : datasets.length === 0 ? (
+          <p className="py-6 text-center text-sm text-muted-foreground">
+            No datasets yet. Upload a corpus and a test set to run an evaluation.
+          </p>
+        ) : (
+          <Table>
+            <TableHeader>
+              <TableRow>
+                <TableHead>Name</TableHead>
+                <TableHead className="text-right">Files</TableHead>
+                <TableHead className="text-right">Questions</TableHead>
+                <TableHead className="w-32" />
+              </TableRow>
+            </TableHeader>
+            <TableBody>
+              {datasets.map((dataset) => (
+                <TableRow key={dataset.id}>
+                  <TableCell className="font-medium">{dataset.name}</TableCell>
+                  <TableCell className="text-right tabular-nums">{dataset.corpus_file_count}</TableCell>
+                  <TableCell className="text-right tabular-nums">{dataset.testset_row_count}</TableCell>
+                  <TableCell className="text-right">
+                    <Button
+                      size="sm"
+                      variant="outline"
+                      disabled={runActive || startMut.isPending}
+                      title={runActive ? "Another run is already in progress" : undefined}
+                      onClick={() => startMut.mutate(dataset.id)}
+                    >
+                      <Play className="mr-1 h-3 w-3" />
+                      Run
+                    </Button>
+                    <ConfirmDialog
+                      title="Delete dataset?"
+                      description={`"${dataset.name}" and its stored files will be removed. Past runs keep their results.`}
+                      onConfirm={() => deleteMut.mutate(dataset.id)}
+                    >
+                      <Button size="sm" variant="ghost" aria-label={`Delete ${dataset.name}`}>
+                        <Trash2 className="h-4 w-4 text-destructive" />
+                      </Button>
+                    </ConfirmDialog>
+                  </TableCell>
+                </TableRow>
+              ))}
+            </TableBody>
+          </Table>
+        )}
+      </CardContent>
+
+      <UploadDialog open={uploadOpen} onOpenChange={setUploadOpen} />
+    </Card>
+  );
+}
+
+function UploadDialog({
+  open,
+  onOpenChange,
+}: {
+  open: boolean;
+  onOpenChange: (open: boolean) => void;
+}) {
+  const queryClient = useQueryClient();
+  const [name, setName] = useState("");
+  const [testset, setTestset] = useState<File | null>(null);
+  const [corpus, setCorpus] = useState<File[]>([]);
+
+  const reset = () => {
+    setName("");
+    setTestset(null);
+    setCorpus([]);
+  };
+
+  const createMut = useMutation({
+    mutationFn: () => createEvalDataset(name, testset as File, corpus),
+    onSuccess: (dataset) => {
+      toast.success(`Dataset "${dataset.name}" created (${dataset.testset_row_count} questions)`);
+      queryClient.invalidateQueries({ queryKey: ["eval-datasets"] });
+      reset();
+      onOpenChange(false);
+    },
+    // The API validates the CSV row by row; surface its message verbatim.
+    onError: (e) => toast.error((e as Error).message),
+  });
+
+  const canSubmit = name.trim() !== "" && testset !== null && corpus.length > 0;
+
+  // Every dismissal path — backdrop, Escape, Cancel — clears the form, so a
+  // reopened dialog never silently resubmits the previous selection.
+  const close = () => {
+    reset();
+    onOpenChange(false);
+  };
+
+  return (
+    <Dialog open={open} onOpenChange={(next) => (next ? onOpenChange(true) : close())}>
+      <DialogContent>
+        <DialogHeader>
+          <DialogTitle>New evaluation dataset</DialogTitle>
+          <DialogDescription>
+            The corpus is re-indexed on every run, which is what the indexing-speed numbers measure.
+          </DialogDescription>
+        </DialogHeader>
+
+        <div className="space-y-4">
+          <div className="space-y-2">
+            <Label htmlFor="eval-dataset-name">Name</Label>
+            <Input
+              id="eval-dataset-name"
+              value={name}
+              onChange={(e) => setName(e.target.value)}
+              placeholder="Support docs — July"
+            />
+          </div>
+          <div className="space-y-2">
+            <Label htmlFor="eval-testset">Test set (CSV)</Label>
+            <Input
+              id="eval-testset"
+              type="file"
+              accept=".csv,text/csv"
+              onChange={(e) => setTestset(e.target.files?.[0] ?? null)}
+            />
+            <p className="text-xs text-muted-foreground">
+              Header: <code>{CSV_HINT}</code>. <code>expected_file_ids</code> is optional and
+              semicolon-separated; rows without it are excluded from hit rate, MRR and recall.
+            </p>
+          </div>
+          <div className="space-y-2">
+            <Label htmlFor="eval-corpus">Corpus files</Label>
+            <Input
+              id="eval-corpus"
+              type="file"
+              multiple
+              onChange={(e) => setCorpus(Array.from(e.target.files ?? []))}
+            />
+            {corpus.length > 0 && (
+              <p className="text-xs text-muted-foreground">{corpus.length} file(s) selected</p>
+            )}
+          </div>
+        </div>
+
+        <DialogFooter>
+          <Button variant="outline" onClick={close}>
+            Cancel
+          </Button>
+          <Button disabled={!canSubmit || createMut.isPending} onClick={() => createMut.mutate()}>
+            {createMut.isPending ? "Uploading…" : "Create"}
+          </Button>
+        </DialogFooter>
+      </DialogContent>
+    </Dialog>
+  );
+}