feat(audit): add pricing signature guards and reporting

Add snapshot, signature, and drift guard support for Vertex AI, Cloudflare Workers AI, and Perplexity API, backed by a queryable audit table and recent-window view.

This commit also wires the audit query layer into daily signal materialization and report generation so structure drift becomes a first-class signal instead of a log-only artifact.

scripts/import_cloudflare_pricing_test.go

@@ -0,0 +1,81 @@
+//go:build llm_script
+
+package main
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestParseCloudflarePricingCatalogBuildsRecords(t *testing.T) {
+	raw, err := os.ReadFile(filepath.Join("testdata", "cloudflare_pricing_sample.md"))
+	if err != nil {
+		t.Fatalf("读取 fixture 失败: %v", err)
+	}
+
+	records, err := parseCloudflarePricingCatalog(string(raw))
+	if err != nil {
+		t.Fatalf("parseCloudflarePricingCatalog 返回错误: %v", err)
+	}
+	if len(records) != 4 {
+		t.Fatalf("期望 4 条 Cloudflare 价格记录，实际 %d", len(records))
+	}
+	if records[0].ModelID != "cloudflare-cf-meta-llama-3-2-1b-instruct" {
+		t.Fatalf("首条 modelID 错误: %q", records[0].ModelID)
+	}
+	if records[1].OutputPrice != 2.253 {
+		t.Fatalf("第二条输出价错误: %v", records[1].OutputPrice)
+	}
+	if records[3].ProviderName != "Moonshot AI" {
+		t.Fatalf("Kimi provider 归一化错误: %q", records[3].ProviderName)
+	}
+}
+
+func TestRunCloudflarePricingImportDryRunPrintsSummary(t *testing.T) {
+	var out bytes.Buffer
+	err := runCloudflarePricingImport(cloudflarePricingImportConfig{
+		URL:     defaultCloudflarePricingFetchURL,
+		Fixture: filepath.Join("testdata", "cloudflare_pricing_sample.md"),
+		DryRun:  true,
+	}, nil, &out)
+	if err != nil {
+		t.Fatalf("runCloudflarePricingImport 返回错误: %v", err)
+	}
+	output := out.String()
+	for _, want := range []string{
+		"source=cloudflare-pricing-import",
+		"models=4",
+		"operator=Cloudflare Workers AI",
+		"dry_run=true",
+	} {
+		if !strings.Contains(output, want) {
+			t.Fatalf("输出缺少 %q，实际: %q", want, output)
+		}
+	}
+}
+
+func TestParseCloudflarePricingCatalogAcceptsFlexibleSectionBoundary(t *testing.T) {
+	raw := `
+## LLM pricing
+
+| Model | Price in Tokens | Price in Neurons |
+| --- | --- | --- |
+| @cf/meta/llama-3.1-8b-instruct | $0.200 per M input tokens  $1.000 per M output tokens | ignored |
+
+## Image generation pricing
+`
+
+	records, err := parseCloudflarePricingCatalog(raw)
+	if err != nil {
+		t.Fatalf("parseCloudflarePricingCatalog 返回错误: %v", err)
+	}
+	if len(records) != 1 {
+		t.Fatalf("期望 1 条 Cloudflare 价格记录，实际 %d", len(records))
+	}
+	if records[0].ModelName != "@cf/meta/llama-3.1-8b-instruct" {
+		t.Fatalf("模型名错误: %q", records[0].ModelName)
+	}
+}