feat: add IP-Adapter Plus (Resampler image projection) support (#1839)

docs/ip_adapter.md

@@ -11,6 +11,10 @@ through a decoupled cross-attention added to every attn2 layer of the
 UNet. It composes with Control Net, so a reference image (appearance) and
 an OpenPose hint (pose) can be combined in a single generation.
 
+Both the classic adapters and the higher-fidelity **Plus** adapters are
+supported; see [Plus variants](#plus-variants) below. The variant is
+detected from the weight file, so the same options work for both.
+
 ## Required weights
 
 1. A base SD 1.5 or SDXL model.
@@ -21,6 +25,11 @@ an OpenPose hint (pose) can be combined in a single generation.
    [h94/IP-Adapter](https://huggingface.co/h94/IP-Adapter):
    - SD 1.5: `models/ip-adapter_sd15.safetensors`
    - SDXL: `sdxl_models/ip-adapter_sdxl_vit-h.safetensors`
+   - SD 1.5 Plus: `models/ip-adapter-plus_sd15.safetensors`
+   - SDXL Plus: `sdxl_models/ip-adapter-plus_sdxl_vit-h.safetensors`
+
+   The Plus files (`ip-adapter-plus_*`) are used exactly like the classic
+   ones; see [Plus variants](#plus-variants).
 
 ## Options
 
@@ -45,6 +54,29 @@ sd-cli -m ..\models\sdxl.safetensors --clip_vision ..\models\clip_vision_h.safet
 The SDXL VAE decode at 1024x1024 is memory heavy; add `--vae-tiling` (and
 `--offload-to-cpu`) on GPUs with limited VRAM.
 
+## Plus variants
+
+The Plus adapters (`ip-adapter-plus_sd15`, `ip-adapter-plus_sdxl_vit-h`)
+replace the small linear image projection with a Resampler (a
+Perceiver-style module with learned latent queries). Instead of pooling the
+CLIP-Vision output into one vector, the Resampler attends over the full grid
+of penultimate CLIP-Vision hidden states and emits more image tokens (16
+instead of 4). The result transfers finer detail and layout from the
+reference, at a small extra cost in the image-projection step.
+
+No extra flags are needed. The variant is detected from the weight file (the
+Resampler's `image_proj.latents` tensor), and every Resampler dimension is
+read from the tensor shapes, so the same `--ip-adapter`,
+`--ip-adapter-image`, and `--ip-adapter-strength` options apply. Plus
+composes with Control Net in the same way as the classic adapters.
+
+```
+sd-cli -m ..\models\sd_v1.5.safetensors --clip_vision ..\models\clip_vision_h.safetensors --ip-adapter ..\models\ip-adapter-plus_sd15.safetensors --ip-adapter-image ..\assets\reference.png --ip-adapter-strength 0.8 -p "a woman, best quality" -n "lowres, bad anatomy" --cfg-scale 7 --steps 30 --sampling-method dpm++2m --scheduler karras -W 512 -H 512
+```
+
+The startup log line `IP-Adapter: 16 image tokens` (versus `4` for the
+classic adapters) confirms a Plus file was loaded.
+
 ## Combining with Control Net
 
 Add the usual Control Net options to keep the reference appearance while