-- Add summary column to snapshots table
-- This stores human-readable summaries of changes (e.g., "3 text blocks changed, 2 new links added")

ALTER TABLE snapshots
ADD COLUMN summary TEXT;

-- Add index for faster queries when filtering by summary existence
CREATE INDEX idx_snapshots_summary ON snapshots(summary) WHERE summary IS NOT NULL;

-- Comment
COMMENT ON COLUMN snapshots.summary IS 'Human-readable change summary generated by simple HTML parsing or AI';
