[Cherry-Pick][OP][Feature] 统一 limit_thinking_content_length CUDA 算子，支持回复长度限制与注入序列 (#6506)

* Initial plan

* feat: migrate core PR6493 changes to release 2.4

Co-authored-by: yuanlehome <23653004+yuanlehome@users.noreply.github.com>

* fix ci

* fix ci

* fix ci

* fix ci

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: yuanlehome <23653004+yuanlehome@users.noreply.github.com>

fastdeploy/engine/sampling_params.py

@@ -71,6 +71,7 @@ class SamplingParams:
             can complete the sequence.
         max_tokens: Maximum number of tokens to generate per output sequence.
         reasoning_max_tokens: Maximum number of tokens to generate for reasoning per output sequence.
+        response_max_tokens: Maximum number of tokens to generate for response per output sequence.
         min_tokens: Minimum number of tokens to generate per output sequence
             before EOS or stop_token_ids can be generated
         logprobs: Number of log probabilities to return per output token.
@@ -97,6 +98,7 @@ class SamplingParams:
     stop_seqs_len: Optional[int] = None
     max_tokens: Optional[int] = None
     reasoning_max_tokens: Optional[int] = None
+    response_max_tokens: Optional[int] = None
     min_tokens: int = 1
     logprobs: Optional[int] = None
     prompt_logprobs: Optional[int] = None
@@ -135,6 +137,7 @@ class SamplingParams:
         stop_token_ids=None,
         max_tokens=None,
         reasoning_max_tokens=None,
+        response_max_tokens=None,
         min_tokens=1,
         logprobs=None,
         prompt_logprobs=None,
@@ -159,6 +162,7 @@ class SamplingParams:
             stop_token_ids=stop_token_ids,
             max_tokens=max_tokens if max_tokens is not None else 8192,
             reasoning_max_tokens=reasoning_max_tokens,
+            response_max_tokens=response_max_tokens,
             min_tokens=min_tokens,
             logprobs=logprobs,
             prompt_logprobs=prompt_logprobs,