[Docs] Update installation method. (#448)

Signed-off-by: Alicia <115451386+congw729@users.noreply.github.com>

docs/getting_started/installation/gpu/cuda.inc.md

@@ -17,6 +17,8 @@ Therefore, it is recommended to install vLLM and vLLM-Omni with a **fresh new**
 # --8<-- [start:pre-built-wheels]
 
 #### Installation of vLLM
+Note: Pre-built wheels are currently only available for vLLM-Omni 0.11.0rc1. For the latest version, please [build from source](https://docs.vllm.ai/projects/vllm-omni/en/latest/getting_started/installation/gpu/#build-wheel-from-source).
+
 
 vLLM-Omni is built based on vLLM. Please install it with command below.
 ```bash

docs/getting_started/quickstart.md

@@ -12,14 +12,17 @@ This guide will help you quickly get started with vLLM-Omni to perform:
 
 ## Installation
 
-For installation on GPU using pre-built-wheel:
+For installation on GPU from source:
 
 ```bash
 uv venv --python 3.12 --seed
 source .venv/bin/activate
-uv pip install vllm==0.11.0 --torch-backend=auto
-uv pip install vllm-omni
+uv pip install vllm==0.12.0 --torch-backend=auto
+git clone https://github.com/vllm-project/vllm-omni.git
+cd vllm-omni
+uv pip install -e .
 ```
+
 For additional details—including alternative installation methods, installation on NPU and other platforms — please see the installation guide in [installation](installation/README.md)
 
 ## Offline Inference