docs: 修正配套代码仓库链接为 SeedVR2-2b-ncnn（原 SeedVR2-ncnn 已 404）

docs: 仓库说明（fp32 基准版）

fp32: merged graph blocks (16 blocks, chunk=2)

fp32: VAE weights

fp32: DiT per-layer weights + Vulkan shaders (part 4)

fp32: DiT per-layer weights + Vulkan shaders (part 3)

fp32: DiT per-layer weights + Vulkan shaders (part 2)

fp32: DiT per-layer weights + Vulkan shaders

connectivity test

initial commit