fix(gitea): redact query params from retry warning logs

Addresses security review finding: retry warnings were logging the full
request URL which could inadvertently leak sensitive query parameters
if future callers pass them.

Added redactURL() helper that:
- Strips query parameters from URLs before logging (replaces with [redacted])
- Returns [invalid URL] for unparseable URLs to avoid leaking any data
- Preserves the base path for debugging context

The error itself (lastErr) is kept as-is since APIError.Error() already
truncates response bodies to 200 chars, and network errors don't contain
user-controlled data.

gitea/client_test.go

@@ -995,3 +995,45 @@ func TestIsRetriableSyscallError(t *testing.T) {
 		})
 	}
 }
+
+func TestRedactURL(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		want  string
+	}{
+		{
+			name:  "no query params",
+			input: "https://gitea.example.com/api/v1/repos/owner/repo/pulls/1",
+			want:  "https://gitea.example.com/api/v1/repos/owner/repo/pulls/1",
+		},
+		{
+			name:  "with query params - redacts",
+			input: "https://gitea.example.com/api/v1/repos/owner/repo/raw/file?ref=main",
+			want:  "https://gitea.example.com/api/v1/repos/owner/repo/raw/file?[redacted]",
+		},
+		{
+			name:  "multiple query params",
+			input: "https://example.com/path?token=secret&page=1",
+			want:  "https://example.com/path?[redacted]",
+		},
+		{
+			name:  "invalid URL",
+			input: "://invalid",
+			want:  "[invalid URL]",
+		},
+		{
+			name:  "empty string",
+			input: "",
+			want:  "",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := redactURL(tt.input)
+			if got != tt.want {
+				t.Errorf("redactURL(%q) = %q, want %q", tt.input, got, tt.want)
+			}
+		})
+	}
+}