### Summary
This PR adds **SigLIP** (Sigmoid Loss Image Pretraining) as a new
embedding model in the LanceDB embedding registry. SigLIP improves
image-text alignment performance using sigmoid-based contrastive loss
and offers robust zero-shot generalization.
Fixes#2498
### What’s Implemented
#### 1. `SigLIP` Embedding Class
* Added `SigLIP` support under `python/lancedb/embeddings/siglip.py`
* Implements:
* `compute_source_embeddings`
* `_batch_generate_embeddings`
* Normalization logic
* Batch-wise progress logging for image embedding
#### 2. Registry Integration
* Registered `SigLIP` in `embeddings/__init__.py`
* `SigLIP` now usable via `connect(..., embedding="siglip")`
#### 3. Evaluation Benchmark Support
* Added SigLIP to `test_embeddings_slow.py` for side-by-side
benchmarking with OpenCLIP and ImageBind
### New Test Methods
#### `test_siglip`
* End-to-end test to verify embeddings table creation and vector shape
for SigLIP
#### `test_siglip_vs_openclip_vs_imagebind_benchmark_full`
* Benchmarks:
* **Recall\@1 / 5 / 10**
* **mAP (Mean Average Precision)**
* **Embedding & Search Latency**
* Dimensionality reporting
### Notes
* SigLIP outputs 768D embeddings (vs 512D for OpenCLIP)
* Benchmark shows competitive performance despite higher dimensionality
* I'm still new to contributing to open-source and learning as I go.
Please feel free to suggest any improvements — I'm happy to make
changes!
This opens up the door for more custom database implementations than the
two we have today. The biggest change should be inivisble:
`ConnectionInternal` has been renamed to `Database`, made public, and
refactored
However, there are a few breaking changes. `data_storage_version` and
`enable_v2_manifest_paths` have been moved from options on
`create_table` to options for the database which are now set via
`storage_options`.
Before:
```
db = connect(uri)
tbl = db.create_table("my_table", data, data_storage_version="legacy", enable_v2_manifest_paths=True)
```
After:
```
db = connect(uri, storage_options={
"new_table_enable_v2_manifest_paths": "true",
"new_table_data_storage_version": "legacy"
})
tbl = db.create_table("my_table", data)
```
BREAKING CHANGE: the data_storage_version, enable_v2_manifest_paths
options have moved from options to create_table to storage_options.
BREAKING CHANGE: the use_legacy_format option has been removed,
data_storage_version has replaced it for some time now
