[CI] Renovation of nightly wheel build & generation (take 2) (#29838)

Signed-off-by: Shengqi Chen <harry-chen@outlook.com>

docs/getting_started/installation/cpu.md

@@ -46,10 +46,23 @@ vLLM is a Python library that supports the following CPU variants. Select your C
 
 ### Pre-built wheels
 
-Currently, there are no pre-built CPU wheels.
+Please refer to the instructions for [pre-built wheels on GPU](./gpu.md#pre-built-wheels).
+
+When specifying the index URL, please make sure to use the `cpu` variant subdirectory.
+For example, the nightly build index is: `https://wheels.vllm.ai/nightly/cpu/`.
 
 ### Build wheel from source
 
+#### Set up using Python-only build (without compilation) {#python-only-build}
+
+Please refer to the instructions for [Python-only build on GPU](./gpu.md#python-only-build), and replace the build commands with:
+
+```bash
+VLLM_USE_PRECOMPILED=1 VLLM_PRECOMPILED_WHEEL_VARIANT=cpu VLLM_TARGET_DEVICE=cpu uv pip install --editable .
+```
+
+#### Full build (with compilation) {#full-build}
+
 === "Intel/AMD x86"
 
     --8<-- "docs/getting_started/installation/cpu.x86.inc.md:build-wheel-from-source"