673cefeb90
JimKarvo's Gitea email (dimitris@jksoftware.gr) differs from Slack email (jimkarvo@gmail.com), so the email-based Slack lookup fails. Add MANUAL_USER_MAPPINGS env var (format: GiteaUsername:SlackID,...) to bypass email lookup when a manual mapping exists. Changes: - cache.go: ParseManualMappings() parses env var format - cache.go: CachedResolver checks manual mappings first (step 0) - main.go: reads MANUAL_USER_MAPPINGS env var, passes to resolver