-- sql/migrations/staging/008_evidence_observed_at.sql
-- Track the timestamp parsed from the actual log line that evidences each
-- issue. This is distinct from first_seen / last_seen, which record when
-- the WHP monitor *detected* the issue. For findings derived from log
-- analysis, evidence_observed_at lets us detect stale, no-longer-relevant
-- issues (e.g. WordPress errors from before a site was rebuilt as static
-- HTML).

ALTER TABLE whp.ai_monitor_issues
    ADD COLUMN IF NOT EXISTS evidence_observed_at DATETIME NULL
        COMMENT 'Timestamp parsed from the log line that supports this issue. NULL when no parseable timestamp was present.';
