feat(scheduler): Launch TP>0 as subprocesses & fit scheduler

[TianyiZhao1437]

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💡 Description

Support TP in scheduler mode.
TODO: Currently we assume node has the same type of GPUs. Need to support different types of GPUs on a single node in the future.

Key Changes

1. Launch tp_rank=0 in the main process and launch tp_rank>0 each in a subprocess.
2. Scheduler is now aware of GPU numbers of each node. Scheduler assigns tp_size in layer allocation.
3. Update deprecated SGL_ENABLE_JIT_DEEPGEMM environment to SGLANG_ENABLE_JIT_DEEPGEMM.

🔗 Related Issues

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• Closes #IssueNumber (e.g., Closes #123)

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