paintplus: vendor the app source and rename from EditmaskwithAI

Bring the full EditmaskwithAI application into the repo under paintplus/
(429 files) so the service is self-contained — the installer copies the
vendored source to ~/docker/paintplus/src instead of cloning at runtime.

Rename to PaintPlus (service + branding; app logic untouched):
- services/editmaskwithai.sh -> services/paintplus.sh (register_service
  paintplus, install_paintplus, ~/docker/paintplus, Caddy paintplus:8000,
  Authelia option preserved)
- container names -> paintplus across docker-compose*.yml; dev network
  -> paintplus-network
- browser <title> -> "PaintPlus - AI Image Editor"; README heading ->
  PaintPlus with upstream provenance note
- README utilities table: editmaskwithai -> paintplus

Backend/frontend code (help strings referencing the old container name,
the ai_photo_edit.db filename) is intentionally left as-is to avoid
touching application logic.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Nb2vJ8W7bHKx1JXVvpCraH

paintplus/Dockerfile

@@ -0,0 +1,68 @@
+# ==============================================================================
+# AI Photo Edit - Unified Container
+# Builds miniPaint frontend and serves it alongside FastAPI backend
+# ==============================================================================
+
+# Stage 1: Build miniPaint frontend
+FROM node:20-alpine AS frontend-build
+
+WORKDIR /frontend
+
+# Copy package files and install dependencies
+COPY frontend/package.json frontend/package-lock.json* ./
+RUN npm install
+
+# Copy frontend source and build
+COPY frontend/ ./
+RUN npm run build
+
+# Stage 2: Python backend with frontend static files
+FROM python:3.11-slim
+
+WORKDIR /app
+
+# Install system dependencies for OpenCV, rembg, SAM, and image processing
+# Note: onnxruntime 1.17+ fixed executable stack issues, no longer need execstack
+RUN apt-get update && apt-get install -y \
+    libgl1 \
+    libglib2.0-0 \
+    libsm6 \
+    libxext6 \
+    libxrender-dev \
+    libgomp1 \
+    wget \
+    git \
+    && rm -rf /var/lib/apt/lists/*
+
+# Copy requirements and install Python dependencies
+COPY backend/requirements.txt .
+RUN pip install --no-cache-dir -r requirements.txt
+
+# Verify rembg loads correctly (model downloads on first use)
+# rembg now supports BiRefNet models which are state-of-the-art for background removal
+RUN python -c "from rembg import remove; print('rembg ready')" || echo "WARNING: rembg not available - Remove Background will be disabled"
+
+# Copy backend application
+COPY backend/ .
+
+# Copy entrypoint script
+COPY backend/entrypoint.sh /entrypoint.sh
+RUN chmod +x /entrypoint.sh
+
+# Copy scripts
+COPY scripts/ /scripts/
+
+# Copy miniPaint frontend files from stage 1
+COPY --from=frontend-build /frontend/index.html /app/static/
+COPY --from=frontend-build /frontend/dist /app/static/dist
+COPY --from=frontend-build /frontend/images /app/static/images
+COPY --from=frontend-build /frontend/src/css /app/static/src/css
+
+# Create data directories
+RUN mkdir -p /app/data/projects /app/data/patches /app/data/models
+
+# Expose port
+EXPOSE 8000
+
+# Use entrypoint script
+ENTRYPOINT ["/entrypoint.sh"]