app/webui: replace generic "see summary.txt" SAT failure text with the real reason

Every place that surfaced a FAILED SAT result — task error messages,
component-status.json detail, and the hardware snapshot's ErrorDescription/
StatusHistory — used to say only "SAT overall_status=FAILED (see
summary.txt)" or "<label> failed", forcing an engineer to go dig through the
run directory to find out what actually broke.

nvidia-config's summary.txt now carries a "warnings" field with the specific
GPU/NVLink finding. A new SATFailureDetail/satFailureDetailFromKV in
component_status_db.go reads that field, or falls back to naming whichever
generic SAT sub-job(s) reported non-OK/UNSUPPORTED status along with their
exit code. This feeds both the task-runner error message and the component
status DB. sat_overlay.go's satKeyStatus (which drives ErrorDescription on
the exported hardware snapshot) now does the same, with storage kept
per-device so one drive's rc doesn't get attributed to another's card.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

audit/internal/webui/tasks.go

@@ -1150,7 +1150,11 @@ func (q *taskQueue) runTask(t *Task, j *jobState, ctx context.Context) {
 		archivePath := app.ExtractArchivePath(archive)
 		if err == nil {
 			if app.ReadSATOverallStatus(archivePath) == "FAILED" {
-				err = fmt.Errorf("SAT overall_status=FAILED (see summary.txt)")
+				if reason := app.SATFailureDetail(archivePath); reason != "" {
+					err = fmt.Errorf("SAT FAILED: %s", reason)
+				} else {
+					err = fmt.Errorf("SAT overall_status=FAILED (see summary.txt)")
+				}
 			}
 		}
 		// A user-aborted run (ctx canceled) may still have produced a partial