fix: miscellaneous quick fixes from CodeRabbit review

- log_info_generate.go: add nil guard in InjectTieredBillingInfo
- billing_expr_request.go: merge headers instead of replacing
- go.mod: remove incorrect // indirect on expr-lang/expr
- ToolPriceSettings.jsx: add null check in syncToVisual
- tool_billing.go: fix PricePer1K for image_generation (per-call, not per-1K)
- utils.jsx: add minute() to time condition regex
- useUsageLogsData.jsx: pass displayMode to renderTieredModelPrice
- AGENTS.md, CLAUDE.md: fix Rule 6/7 ordering
- relay-gemini.go: add TEXT modality case in CandidatesTokensDetails

service/tool_billing.go

@@ -74,7 +74,7 @@ func ComputeToolCallQuota(usage ToolCallUsage, groupRatio float64) ToolCallResul
 		items = append(items, ToolCallItem{
 			Name:       "image_generation",
 			CallCount:  1,
-			PricePer1K: price * 1000,
+			PricePer1K: price,
 			TotalPrice: price,
 			Quota:      quota,
 		})