v1.5.3

Summary

• Add rootsandfruit/purge-breeze-cache — server-side Breeze purge (all cache or optional post_id).
• set-post-author accepts purge_breeze: true to purge in the same call.
• ping reports breeze_active; set-post-author returns breeze_purge_command when manual purge still needed.

Test plan

• Git Updater installs abilities-1.5.3.zip on production
• audit-mcp-abilities.ps1 lists rootsandfruit/purge-breeze-cache
• Execute purge ability; confirm logged-out HTML updates without cache-bust query string
• set-post-author with purge_breeze: true clears byline cache on preview URLs