Studio: show total chunks in the aggregate indexing toast

The completion toast reported only document count. Capture each job's
num_chunks from its complete event into the index-progress store and sum
across the batch, so the toast reads 'N documents and M chunks indexed'.
Already-indexed (deduped) files contribute 0 new chunks.

studio/frontend/src/features/chat/hooks/use-thread-doc-uploads.ts

@@ -204,7 +204,7 @@ export function useThreadDocUploads(): UseThreadDocUploadsResult {
                     .getState()
                     .setRagSource({ kind: "thread" });
                 }
-                indexProgress.setReady(localChipId);
+                indexProgress.setReady(localChipId, event.num_chunks);
                 releaseSlot();
               } else if (event.type === "error") {
                 setPendingDocs((prev) =>

studio/frontend/src/features/chat/shared-composer.tsx

@@ -694,7 +694,7 @@ export function SharedComposer({
                     .getState()
                     .setRagSource({ kind: "thread" });
                 }
-                indexProgress.setReady(localChipId);
+                indexProgress.setReady(localChipId, event.num_chunks);
                 releaseSlot();
               } else if (event.type === "error") {
                 setPendingDocs((prev) =>

studio/frontend/src/features/rag/components/ingestion-toast-stack.tsx

@@ -27,6 +27,7 @@ export function IngestionToastStack() {
     (e) => e.status === "ready" || e.status === "error",
   ).length;
   const errored = items.filter((e) => e.status === "error").length;
+  const totalChunks = items.reduce((sum, e) => sum + (e.chunks || 0), 0);
   const allDone = total > 0 && done === total;
   // Overall progress: completed/errored files count as 1, in-flight files
   // contribute their fractional progress. Smooth even for a handful of files.
@@ -74,7 +75,8 @@ export function IngestionToastStack() {
   if (allDone) {
     const indexed = total - errored;
     subtitle =
-      `${indexed} document${indexed === 1 ? "" : "s"} indexed` +
+      `${indexed} document${indexed === 1 ? "" : "s"} and ` +
+      `${totalChunks} chunk${totalChunks === 1 ? "" : "s"} indexed` +
       (errored > 0 ? ` · ${errored} failed` : "");
   } else {
     subtitle = `${done}/${total} · ${pct}%`;

studio/frontend/src/features/rag/stores/index-progress-store.ts

@@ -16,6 +16,8 @@ export interface IndexEntry {
   status: IndexEntryStatus;
   /** 0..1; only meaningful while `indexing`. */
   progress: number;
+  /** Chunks this file produced (from the job's complete event); 0 until done. */
+  chunks: number;
 }
 
 interface IndexProgressState {
@@ -23,7 +25,7 @@ interface IndexProgressState {
   add: (id: string, filename: string) => void;
   setIndexing: (id: string) => void;
   setProgress: (id: string, progress: number) => void;
-  setReady: (id: string) => void;
+  setReady: (id: string, chunks?: number) => void;
   setError: (id: string) => void;
   clear: () => void;
 }
@@ -46,13 +48,14 @@ export const useIndexProgressStore = create<IndexProgressState>((set) => ({
     set((s) => ({
       entries: {
         ...s.entries,
-        [id]: { filename, status: "queued", progress: 0 },
+        [id]: { filename, status: "queued", progress: 0, chunks: 0 },
       },
     })),
   setIndexing: (id) => patch(set, id, { status: "indexing" }),
   setProgress: (id, progress) =>
     patch(set, id, { status: "indexing", progress }),
-  setReady: (id) => patch(set, id, { status: "ready", progress: 1 }),
+  setReady: (id, chunks = 0) =>
+    patch(set, id, { status: "ready", progress: 1, chunks }),
   setError: (id) => patch(set, id, { status: "error" }),
   clear: () => set({ entries: {} }),
 }));