fix: recognize case-insensitive signed URL schemes across log paths

internal/logging/redact.go

@@ -158,7 +158,7 @@ func RedactJSON(body []byte) (string, error) {
 }
 
 var (
-	urlInText         = regexp.MustCompile(`(?:https?|wss?)://[^\s<>"']+`)
+	urlInText         = regexp.MustCompile(`(?i)(?:https?|wss?)://[^\s<>"']+`)
 	authHeaderInText  = regexp.MustCompile(`(?im)\b(?:proxy-authorization|authorization|set-cookie|cookie)["']?\s*[=:]\s*[^\r\n]+`)
 	privatePEMInText  = regexp.MustCompile(`(?s)-----BEGIN [A-Z0-9 ]*PRIVATE KEY-----.*?(?:-----END [A-Z0-9 ]*PRIVATE KEY-----|$)`)
 	sensitiveTextLine = regexp.MustCompile(`(?im)\b(?:prompt|system[_-]?prompt|messages|transcript|text|content|audio|closing[_-]?remark)\s*[=:]\s*[^\r\n]+`)

internal/logging/text_security_test.go

@@ -61,6 +61,60 @@ func TestContentFieldClassificationAndEveryLoggingPathAgree(t *testing.T) {
 	}
 }
 
+func TestURLSchemeCaseCannotExposeSignedPartsOnAnyLoggingPath(t *testing.T) {
+	for _, scheme := range []string{"http", "HTTP", "HtTp", "https", "HTTPS", "hTtPs", "ws", "WS", "wS", "wss", "WSS", "wSs"} {
+		signed := scheme + "://storage.example/audio.wav?sv=2025-01-05&se=2026-10-10&sig=private-signature-value"
+		for _, debug := range []bool{false, true} {
+			out := installTestLogger(t, debug)
+			for _, media := range []string{"text/plain", "application/json"} {
+				body := "upload failed: " + signed
+				if media == "application/json" {
+					body = `{"resource":"` + signed + `","task_id":4,"status":"ready"}`
+				}
+				ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+					got, err := io.ReadAll(r.Body)
+					if err != nil || string(got) != body {
+						t.Error("wire request changed", err)
+					}
+					w.Header().Set("Content-Type", media)
+					_, _ = io.WriteString(w, body)
+				}))
+				req, err := http.NewRequest(http.MethodPost, ts.URL, strings.NewReader(body))
+				if err != nil {
+					t.Fatal(err)
+				}
+				req.Header.Set("Content-Type", media)
+				response, err := HTTPClient(ts.Client(), "test.url", "upstream").Do(req)
+				if err != nil {
+					ts.Close()
+					t.Fatal(err)
+				}
+				got, err := io.ReadAll(response.Body)
+				_ = response.Body.Close()
+				ts.Close()
+				if err != nil || string(got) != body {
+					t.Fatal("wire response changed", err)
+				}
+				slog.Error("upload failed", "error", errors.New(body), "detail", body)
+				slog.Error(body)
+			}
+			text := out.String()
+			if strings.Contains(text, "private-signature-value") || strings.Contains(text, "sv=2025") || strings.Contains(text, "se=2026") {
+				t.Fatalf("scheme %s debug %v leak: %s", scheme, debug, text)
+			}
+			for _, keep := range []string{"upload failed", "audio.wav", "task_id", "ready"} {
+				if !strings.Contains(text, keep) {
+					t.Fatal("safe diagnostic lost", text)
+				}
+			}
+			plain := scheme + "://storage.example/public.wav"
+			if got := cleanString(plain); got != plain {
+				t.Fatal("unsigned URL changed", got)
+			}
+		}
+	}
+}
+
 func TestPercentEncodedSingleAndMixedFormsKeepWireBytesAndHideSecrets(t *testing.T) {
 	for _, body := range []string{
 		"%74oken=private-access-token",