Heuristic spam detector with 50+ patterns including SPF/DKIM/DMARC auth checks, display name impersonation, URL analysis, attachment risk scoring, and advanced phishing detection (fake quarantine reports, voicemail scams, cold email solicitation). Configurable via SpamDetectorConfig.json with customizable weights and blocklist. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>