Configure monorepo build: unified CI, local deps, .dockerignore

- Dockerfiles use monorepo root as build context
- common/ and core/ installed as local packages (no git+https)
- Client tarball built from local client/ dir
- Unified CI with change detection: common/core -> rebuild both
- Per-repo CI workflows removed

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

l2/Dockerfile

@@ -1,23 +1,23 @@
 FROM python:3.11-slim
-
 WORKDIR /app
 
-# Install git for pip to clone dependencies
 RUN apt-get update && apt-get install -y --no-install-recommends git && rm -rf /var/lib/apt/lists/*
 
-# Install dependencies
-COPY requirements.txt .
+# Install common as local package (no more git+https)
+COPY common/ /tmp/common/
+RUN pip install --no-cache-dir /tmp/common/ && rm -rf /tmp/common
+
+# Install L2 dependencies
+COPY l2/requirements.txt .
 ARG CACHEBUST=1
 RUN pip install --no-cache-dir -r requirements.txt
 
-# Copy application
-COPY . .
+# Copy L2 application
+COPY l2/ .
 
-# Create data directory
 RUN mkdir -p /data/l2
 
 ENV PYTHONUNBUFFERED=1
 ENV ARTDAG_DATA=/data/l2
 
-# Default command runs the server
 CMD ["python", "server.py"]