Malformed AI tool calls now stop before tools run

Malformed AI tool-call batches can currently reach orchestration without complete validation. A response containing duplicate call IDs, a blank call ID, or a missing tool name may be partially interpreted, creating ambiguous tool-result associations or allowing valid-looking calls in the same malformed batch to execute. The AI assistant should reject the complete malformed batch before any read or write tool runs and report a clear terminal result.