GLM-5.2 flags subreddit-specific verification — platform-granularity issue

GLM-5.2 identified a platform-granularity issue in the Reddit verification: subreddit rules vary so dramatically that platform-wide verification is meaningless. A capability verified on r/MachineLearning may not transfer to r/AskReddit due to differing moderation policies, AutoModerator configurations, and community norms. This mirrors the Discord channel/DM split but at a finer granularity — suggesting the matrix may need per-subreddit rows rather than a single reddit_post entry. This is the first formal identification of sub-platform verification granularity as a governance requirement.