[misc] pin fastvideo-kernel in .toml file (#989)

docs/getting_started/installation.md

@@ -11,15 +11,13 @@ FastVideo supports the following hardware platforms:
 ### Using pip
 
 ```bash
+# Create and activate a new conda environment
+conda create -n fastvideo python=3.12
+conda activate fastvideo
+
 pip install fastvideo
 ```
 
-### Using conda
-
-```bash
-conda install -c conda-forge fastvideo
-```
-
 ### From source
 
 ```bash
@@ -28,6 +26,12 @@ cd FastVideo
 pip install -e .
 ```
 
+Also optionally install flash-attn:
+
+```bash
+pip install flash-attn --no-build-isolation
+```
+
 ## Hardware Requirements
 
 - **NVIDIA GPUs**: CUDA 11.8+ with compute capability 7.0+

docs/getting_started/quick_start.md

@@ -15,6 +15,12 @@ conda activate fastvideo
 pip install fastvideo
 ```
 
+Also optionally install flash-attn:
+
+```bash
+pip install flash-attn --no-build-isolation
+```
+
 ## Basic Usage
 
 ### Text-to-Video Generation