Initial scaffold: Flask webui + APScheduler + Playwright automation for MassPrice rule scheduling

Drives massprice.tcgplayer.com's Run Rule action per-rule on a
user-configured schedule (multiple times/day, day-of-week toggles),
replacing MassPrice's native scheduler (capped at 15 schedules
account-wide, one run/day, with observed clock drift). Deployed via
Forgejo push-to-deploy on Unraid, matching arr-summary/card-grader.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01H6TgffxTvYhqxykAbVQg2v

docker-compose.yml

@@ -0,0 +1,21 @@
+services:
+  massprice:
+    build: .
+    container_name: massprice
+    # Headless Chromium's default /dev/shm (64MB) is too small in Docker
+    # and causes renderer crashes — this is the standard mitigation.
+    shm_size: "1gb"
+    ports:
+      - "${HOST_PORT:-5056}:5000"
+    volumes:
+      # Schedules, run history, the rule-name cache, and the saved
+      # MassPrice login session must outlive `up -d --build`, which
+      # recreates the container and discards its filesystem.
+      - ./data:/data
+    environment:
+      - LOGIN_PASSWORD=${LOGIN_PASSWORD}
+      - SECRET_KEY=${SECRET_KEY}
+      - MASSPRICE_USERNAME=${MASSPRICE_USERNAME}
+      - MASSPRICE_PASSWORD=${MASSPRICE_PASSWORD}
+      - TZ=${TZ:-America/New_York}
+    restart: unless-stopped