fix: AUTO tier order ascending + stats/CSV export completeness + UI key-view toggle & exit affordance

- scheduler: BuildChain sorts tiers ascending so tier 1 (highest priority) is tried first; previously descending inverted the chain (P10-1..P10-5)
- stats/api: handleStatsAPI limit→20000; CSV reads full audit via new Stats.AuditRecords (includes *.old rotation); key_names mapped by keyID() masked key; non-admin filter and keys-csv use masked keys
- server: ring buffer NewStats(10000)
- ui: dash-row card scroll area moved to table container (fix overflow below card); key view toggle (re-click same key returns to global) + kpi-exit affordance; rec-exit span
- chat: chain-failure record now surfaces first failed tier; AUTO comment sync

internal/gateway/stats.go

@@ -395,6 +395,51 @@ func (s *Stats) Records(from, to int64, key string) []Req {
 	return out
 }
 
+// AuditRecords returns every request row from the audit file plus its rotated
+// .old files within the [from,to] unix-millisecond window, optionally for one
+// masked key id. Unlike Records it is not bounded by the in-memory ring, so it
+// yields a complete history for CSV export regardless of restarts or churn.
+func (s *Stats) AuditRecords(from, to int64, key string) []Req {
+	s.mu.Lock()
+	path := s.auditPath
+	s.mu.Unlock()
+	if path == "" {
+		return nil
+	}
+	files := []string{path}
+	if olds, err := filepath.Glob(path + ".*.old"); err == nil {
+		files = append(files, olds...)
+	}
+	var out []Req
+	for _, p := range files {
+		f, err := os.Open(p)
+		if err != nil {
+			continue
+		}
+		sc := bufio.NewScanner(f)
+		sc.Buffer(make([]byte, 64*1024), 16*1024*1024)
+		for sc.Scan() {
+			var r Req
+			if json.Unmarshal(sc.Bytes(), &r) != nil || r.Type == "" {
+				continue
+			}
+			if key != "" && r.Key != key {
+				continue
+			}
+			if from > 0 && r.Time < from {
+				continue
+			}
+			if to > 0 && r.Time > to {
+				continue
+			}
+			out = append(out, r)
+		}
+		f.Close()
+	}
+	sort.Slice(out, func(i, j int) bool { return out[i].Time < out[j].Time })
+	return out
+}
+
 // Snapshot returns the whole dashboard payload; when key != "" the records
 // and aggregate views are restricted to that gateway key.
 func (s *Stats) Snapshot(limit int, key string) map[string]interface{} {