• [FIX] Prevent HTTP/3 response stalls and DATA writes while headers are pending after informational responses such as 103 Early Hints.
• [FIX] Reject response-only tags in gQUIC client hellos to prevent crashes.
• [FIX] Handle truncated gQUIC resumption certificates and allocation failures safely.
• [FIX] Avoid undefined behavior in packet-header generation, stream queue offsets, and structured-field parser allocations (#702).