Hexagon: Add ARGSORT operation

[max-krasnyansky]

Implemented ARGSORT operation for the Hexagon backend.

• Added HTP_OP_ARGSORT to htp-msg.h
• Added op_argsort declaration to htp-ops.h
• Implemented op_argsort in argsort-ops.c using a scalar quicksort algorithm running on the DSP, with HVX for data movement.
• Updated main.c to dispatch ARGSORT requests.
• Updated ggml-hexagon.cpp to register the operation and handle graph compute.
• Updated CMakeLists.txt to include the new source file.
• Included contiguous memory checks in ggml_hexagon_supported_argsort.

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PR created automatically by Jules for task 17121120659402425543 started by @max-krasnyansky

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