Hotfix: Update rembg model string from bria to bria-rmbg for correct session mapping

Fix: Shift Bria RMBG execution to rembg ONNX runtime to resolve transformers package conflict entirely

Fix: HF Space 503 Startup Crash - downgrade transformers to 4.38.2 to fix RMBG tied weights bug

Fix: Pivot to briaai/RMBG-1.4 for reliable graphic alpha-matting instead of SAM

Hotfix: Update Dockerfile to bake transformers SAM weights

Fix: Replace rembg with Ultralytics MobileSAM for mathematically perfect vector masking

Fix: replace deprecated libgl1-mesa-glx with libgl1

Initial: FastAPI + Grounding DINO asset extraction API