Fix Docker build: add missing deps and .dockerignore

- Replace deprecated libgl1-mesa-glx with libgl1 (Debian Trixie)
- Add CLIP, einops, ftfy, regex dependencies for DeepGaze models
- Add backend .dockerignore to exclude .venv (128MB → 1.6MB context)
- Update Makefile with CLIP install step
- All 3 models load successfully in Docker

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Makefile

@@ -8,6 +8,7 @@ setup-backend:
 	cd backend && .venv/bin/pip install --upgrade pip
 	cd backend && .venv/bin/pip install -e ".[dev]"
 	cd backend && .venv/bin/pip install "deepgaze-pytorch @ git+https://github.com/matthias-k/DeepGaze.git"
+	cd backend && .venv/bin/pip install "clip @ git+https://github.com/openai/CLIP.git"
 
 setup-frontend:
 	cd frontend && npm install

backend/.dockerignore

@@ -0,0 +1,6 @@
+.venv
+__pycache__
+*.pyc
+data/
+.env
+.pytest_cache

backend/Dockerfile

@@ -3,7 +3,7 @@ FROM python:3.12-slim
 WORKDIR /app
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
-    libgl1-mesa-glx libglib2.0-0 curl git && \
+    libgl1 libglib2.0-0 curl git && \
     rm -rf /var/lib/apt/lists/*
 
 # Copy dependency spec first for layer caching
@@ -11,6 +11,8 @@ COPY pyproject.toml .
 
 # Install dependencies (non-editable, just deps)
 RUN pip install --no-cache-dir . && \
+    pip install --no-cache-dir einops ftfy regex && \
+    pip install --no-cache-dir "clip @ git+https://github.com/openai/CLIP.git" && \
     pip install --no-cache-dir "deepgaze-pytorch @ git+https://github.com/matthias-k/DeepGaze.git"
 
 # Copy application source