Feat: Adds a new feature that enables the LLM to extract a structured table of contents (TOC) directly from plain text. (#10428)

### What problem does this PR solve?

**Adds a new feature that enables the LLM to extract a structured table
of contents (TOC) directly from plain text.**
_This implementation prioritizes efficiency over reasoning — the model
runs in a strictly deterministic mode (thinking disabled) to minimize
latency.
As a result, overall performance may be less optimal, but the extraction
speed and consistency are guaranteed._

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

rag/llm/chat_model.py

@@ -133,6 +133,7 @@ class Base(ABC):
             "logprobs",
             "top_logprobs",
             "extra_headers",
+            "enable_thinking"
         }
 
         gen_conf = {k: v for k, v in gen_conf.items() if k in allowed_conf}