Give the UTC stamp a buffer GCC can prove is big enough

src/core/Application.cpp

@@ -95,7 +95,13 @@ std::string utcStampNow() {
 #else
     gmtime_r(&t, &tm);
 #endif
-    char b[32];
+    // 64, not 32, purely to keep the compiler quiet. The real output is always 17
+    // characters, but the tm fields are plain ints, so GCC cannot rule out a
+    // nonsense clock and computes a worst case of 61 bytes - warning on every
+    // build. snprintf truncates rather than overflows either way, so this was
+    // never a safety problem; a recurring warning that everyone learns to ignore
+    // is the actual cost.
+    char b[64];
     std::snprintf(b, sizeof(b), "%04d-%02d-%02dT%02d:%02dZ", tm.tm_year + 1900, tm.tm_mon + 1,
                   tm.tm_mday, tm.tm_hour, tm.tm_min);
     return std::string(b);