chore: move plugins/ to separate repo, gitignore the directory

plugins/ is now tracked at bvandeusen/fabledscryer-plugins.
Removed tracked traefik files from this repo's index (files remain on disk).
Added plugins/ to .gitignore so the directory is ignored going forward.

PLUGIN_DIR in config.yaml still points to plugins/ for local dev and Docker.

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

plugins/traefik/plugin.yaml

@@ -1,10 +0,0 @@
-# plugins/traefik/plugin.yaml
-name: traefik
-version: "1.0.0"
-description: "Traefik reverse proxy metrics integration"
-author: ""
-min_app_version: "0.1.0"
-
-config:
-  metrics_url: "http://localhost:8080/metrics"
-  scrape_interval_seconds: 60