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/server.go

@@ -38,7 +38,7 @@ func New(c *core.Core, gatewayKeys []string) (*Gateway, error) {
 	if err != nil {
 		return nil, err
 	}
-	st := NewStats(3000)
+	st := NewStats(10000)
 	if cfg := c.Config(); cfg != nil && cfg.RuntimeFile != "" {
 		st.LoadAudit(cfg.RuntimeFile + ".audit.jsonl")
 	}