Filtering UX: overview results, auto-clear on re-run, config save fix

- Add filtering results summary card on round Overview tab with pass/fail/flag
  counts and color-coded progress bar (polls every 5s)
- Auto-delete previous filtering results when re-running so new ones stream in
- Rename BUSINESS_CONCEPT to "Concept" in filtering results to prevent overflow
- Fix config save race condition where toggling switches (aiParseFiles, advance
  counts) would revert: pendingSaveRef cleared before refetch completed

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/server/routers/filtering.ts

@@ -493,6 +493,11 @@ export const filteringRouter = router({
         })
       }
 
+      // Clear previous filtering results so new ones stream in fresh
+      await ctx.prisma.filteringResult.deleteMany({
+        where: { roundId: input.roundId },
+      })
+
       const job = await ctx.prisma.filteringJob.create({
         data: {
           roundId: input.roundId,