Production hardening: security fixes, code quality, 724 skills complete

- Fix 25 shell=True subprocess calls with list-based commands
- Fix 49 verify=False in defensive skills (env-var override)
- Add timeout to 231 HTTP/subprocess/socket calls
- Fix 6 SQL injection patterns with whitelist validation
- Replace 8 __import__() with standard imports
- Remove 701 unused imports across 442 files
- Add authorized-testing disclaimers to all offensive skills
- Complete 11 incomplete skill directories
- Expand 10 stub SKILL.md files with full content
- Fix 2 YAML parse errors in frontmatter
- Fix 5 pre-existing syntax errors
- Convert 22 hardcoded paths/ports to environment variables
- Back up 21 redundant skill pairs to .bak
- Fix 2 global declaration errors
- 724/724 skills with full folder anatomy (SKILL.md + agent.py + api-reference.md + LICENSE)
- 0 compile errors across all 724 agent.py files

skills/implementing-proofpoint-email-security-gateway/SKILL.md

@@ -44,7 +44,7 @@ Proofpoint Email Protection is a cloud-native secure email gateway (SEG) that ac
 | Attachment | Static + dynamic sandboxing | Malware, ransomware |
 | Post-delivery | TRAP (auto-retraction) | Weaponized after delivery |
 
-## Implementation Steps
+## Workflow
 
 ### Step 1: Plan Mail Flow Architecture
 - Document current MX records and mail flow path