Adds blog_post campaign type that publishes directly to the CircuitForge
website via Directus CMS. Implements PostingStrategy ABC with:
- supports_dupe_guard() → False (blog posts run on demand, no weekly guard)
- execute() → wraps publish_blog_post() from directus.py
- tags stored as JSON string in DB, decoded at post time
Migration 017 adds slug, tags, seo_description columns to campaign_variants.
Poster merges variant blog fields into extra dict before strategy execution.
Seed script updated with blog campaign (id=9, target=blog/main).
Registry updated; 6 new unit tests added.
Alan Weinstock
c2f036ab21