deepseek v3.2 support

[hksdpc255]

Deepseek V3.2 uses a new tool-call format like this:

<｜DSML｜function_calls>
<｜DSML｜invoke name="get_datetime">
<｜DSML｜parameter name="timezone" string="true">Asia/Shanghai</｜DSML｜parameter>
</｜DSML｜invoke>
</｜DSML｜function_calls>

<｜DSML｜function_calls>
<｜DSML｜invoke name="search">
<｜DSML｜parameter name="query" string="true">search agent benchmark 2024</｜DSML｜parameter>
<｜DSML｜parameter name="topn" string="false">10</｜DSML｜parameter>
<｜DSML｜parameter name="source" string="true">web</｜DSML｜parameter>
</｜DSML｜invoke>
<｜DSML｜invoke name="search">
<｜DSML｜parameter name="query" string="true">搜索智能体 基准测试</｜DSML｜parameter>
<｜DSML｜parameter name="topn" string="false">10</｜DSML｜parameter>
<｜DSML｜parameter name="source" string="true">web</｜DSML｜parameter>
</｜DSML｜invoke>
</｜DSML｜function_calls>

Maybe we should update the polyfill detection code for this.