Add Pixio as external encoder

[xlei77]

This PR integrates Pixio, an image encoder, into MapAnything to enable benchmarking against other SOTA encoders (e.g., DINO series).

Changes

1. Model Definitions & Wrapper — Added Pixio model definitions and a wrapper to integrate it with the MapAnything architecture.
2. Configuration — Added YAML configs for the Pixio ViT-H/16 checkpoint.
3. Benchmark Script — Added a script to run performance benchmarks on Pixio.
4. Lazy Instantiation Support — Modified model.py to support lazy instantiation of encoder classes from /mapanything/models/external/.

Testing

Manual validation was performed by running benchmark scripts on an H100 node and running local demos.

Benchmark:

bash bash_scripts/benchmark/dense_2_view/pixio.sh <CHECKPOINT_PATH> <OUTPUT_DIR>

Local Demo:

python scripts/demo_local_weight.py \
    --image_folder <INPUT_IMAGES_DIR> \
    --local_config '{
        "path": "configs/train.yaml",
        "model_str": "pixio",
        "checkpoint_path": "<CHECKPOINT_PATH>",
        "config_overrides": [
            "machine=aws",
            "model=pixio",
            "model/task=images_only",
            "model.encoder.uses_torch_hub=false"
        ],
        "trained_with_amp": true,
        "trained_with_amp_dtype": "bf16",
        "data_norm_type": "dinov2",
        "patch_size": 16,
        "resolution": 512,
        "strict": false
    }' \
    --output_path <OUTPUT_FILE>

Note: A README with detailed instructions for running benchmarks and demos will be added in a follow-up.

Performance

See benchmark results here: Pixio Performance

Dependencies

None.

Breaking Changes

None.