Show T5 products in the client's shop; keep float IDs and unknown paths off IMVU

The shop's T5 filter (maturity_rating "t5") is answered from the hub's products, fetched so they can be
shown and tried on; buying T5 products adds them to the hub library, and product.php details for
community products are answered here.

The client sends some product IDs as floats ("2000000008.0"): product.php passed the worn community
product to IMVU that way. Every ID is now read either way, and products.Guard refuses any request to
IMVU that still names a local ID given out. T5DE_PROXY_DUMP logs request and response bodies.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

internal/proxy/dump.go

@@ -0,0 +1,33 @@
+package proxy
+
+import (
+	"log"
+	"net/http"
+	"strings"
+)
+
+// Dump logs the request and response bodies of requests whose path contains Match (T5DE_PROXY_DUMP, for finding
+// out what IMVU's APIs send). It may log personal data: only for test accounts.
+type Dump struct {
+	Match string
+	Log   *log.Logger
+}
+
+func (d Dump) Intercept(x *Exchange) error {
+	if d.Match == "" || !strings.Contains(x.URL.Path, d.Match) {
+		return nil
+	}
+	d.Log.Printf("dump: %s %s\n%s", x.Request.Method, x.URL, x.Body)
+	next := x.ModifyResponse
+	x.ModifyResponse = func(resp *http.Response, body []byte) ([]byte, error) {
+		if next != nil {
+			var err error
+			if body, err = next(resp, body); err != nil {
+				return nil, err
+			}
+		}
+		d.Log.Printf("dump: %s answered %d\n%s", x.URL.Path, resp.StatusCode, body)
+		return body, nil
+	}
+	return nil
+}