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

gunicorn.conf.py

@@ -0,0 +1,13 @@
+# Gunicorn configuration
+import os
+
+# Exactly one worker: APScheduler and the Playwright run-queue live in
+# process memory, not a shared store — a second worker would duplicate
+# every scheduled job and run each rule twice. Fine for a low-traffic
+# single-user admin tool.
+workers = 1
+threads = 4
+worker_class = "gthread"
+bind = "0.0.0.0:" + os.environ.get("PORT", "5000")
+timeout = 120  # a rule run launches Chromium, logs in, and clicks through
+keepalive = 5