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/backend/app/models/edit.py

@@ -0,0 +1,23 @@
+from sqlalchemy import Column, Integer, String, DateTime, ForeignKey, Text
+from sqlalchemy.orm import relationship
+from datetime import datetime
+from app.database import Base
+
+
+class Edit(Base):
+    __tablename__ = "edits"
+
+    id = Column(Integer, primary_key=True, index=True)
+    project_id = Column(Integer, ForeignKey("projects.id"), nullable=False)
+    created_at = Column(DateTime, default=datetime.utcnow)
+    mode = Column(String, nullable=False)  # "A" or "B"
+    prompt = Column(Text, nullable=False)
+    selection_type = Column(String, nullable=False)  # "rectangle", "ellipse", "lasso"
+    bbox_json = Column(Text, nullable=False)  # JSON string of {x, y, width, height}
+    feather_px = Column(Integer, default=0)
+    ai_provider = Column(String, nullable=False)
+    status = Column(String, nullable=False)  # "pending", "processing", "completed", "failed"
+    error_message = Column(Text, nullable=True)
+
+    # Relationships
+    project = relationship("Project", back_populates="edits")