feat: add DAG progress dots to browse page via WebSocket events

- Add TRANSCRIPT_DAG_STATUS handler to UserEventsProvider with
  DagStatusContext and useDagStatusMap hook for live DAG task updates
- Clean up dagStatusMap entries when TRANSCRIPT_STATUS transitions
  away from "processing"
- Create DagProgressDots component rendering color-coded dots per
  DAG task (green=completed, blue pulsing=running, hollow=queued,
  red=failed, gray=cancelled) with humanized tooltip names
- Wire dagStatusMap through browse page -> TranscriptCards ->
  TranscriptStatusIcon, falling back to REST dag_status field

www/app/(app)/browse/_components/TranscriptCards.tsx

@@ -19,6 +19,7 @@ import {
   generateTextFragment,
 } from "../../../lib/textHighlight";
 import type { components } from "../../../reflector-api";
+import type { DagTask } from "../../../lib/UserEventsProvider";
 
 type SearchResult = components["schemas"]["SearchResult"];
 type SourceKind = components["schemas"]["SourceKind"];
@@ -29,6 +30,7 @@ interface TranscriptCardsProps {
   isLoading?: boolean;
   onDelete: (transcriptId: string) => void;
   onReprocess: (transcriptId: string) => void;
+  dagStatusMap?: Map<string, DagTask[]>;
 }
 
 function highlightText(text: string, query: string): React.ReactNode {
@@ -102,11 +104,13 @@ function TranscriptCard({
   query,
   onDelete,
   onReprocess,
+  dagStatusMap,
 }: {
   result: SearchResult;
   query: string;
   onDelete: (transcriptId: string) => void;
   onReprocess: (transcriptId: string) => void;
+  dagStatusMap?: Map<string, DagTask[]>;
 }) {
   const [isExpanded, setIsExpanded] = useState(false);
 
@@ -137,7 +141,18 @@ function TranscriptCard({
     <Box borderWidth={1} p={4} borderRadius="md" fontSize="sm">
       <Flex justify="space-between" alignItems="flex-start" gap="2">
         <Box>
-          <TranscriptStatusIcon status={result.status} />
+          <TranscriptStatusIcon
+            status={result.status}
+            dagStatus={
+              dagStatusMap?.get(result.id) ??
+              (
+                (result as Record<string, unknown>).dag_status as
+                  | { tasks?: DagTask[] }
+                  | undefined
+              )?.tasks ??
+              null
+            }
+          />
         </Box>
         <Box flex="1">
           {/* Title with highlighting and text fragment for deep linking */}
@@ -284,6 +299,7 @@ export default function TranscriptCards({
   isLoading,
   onDelete,
   onReprocess,
+  dagStatusMap,
 }: TranscriptCardsProps) {
   return (
     <Box position="relative">
@@ -315,6 +331,7 @@ export default function TranscriptCards({
               query={query}
               onDelete={onDelete}
               onReprocess={onReprocess}
+              dagStatusMap={dagStatusMap}
             />
           ))}
         </Stack>