feat: remove Enterprise badges, simplify Pro upgrade prompts

- Replace barrel import in AuditLogPanel.tsx to fix ad-blocker crash
- Remove all Enterprise/Pro badges from nav and feature headers
- Simplify upgrade CTAs to clean 'Upgrade to Pro' links
- Update docs: PULSE_PRO.md, API.md, README.md, SECURITY.md
- Align terminology: single Pro tier, no separate Enterprise tier

Also includes prior refactoring:
- Move auth package to pkg/auth for enterprise reuse
- Export server functions for testability
- Stabilize CLI tests

docs/API.md

@@ -201,7 +201,7 @@ Returns a new raw token (shown once) and updates stored hashes:
 
 ---
 
-## 🧾 Audit Log (Enterprise)
+## 🧾 Audit Log (Pro)
 
 These endpoints require admin access and the `settings:read` scope. In OSS builds, the list endpoint returns an empty set and `persistentLogging: false`.
 

docs/PULSE_PRO.md

@@ -4,7 +4,7 @@ Pulse Pro unlocks advanced AI automation features on top of the free Pulse platf
 
 ## What You Get
 
-### Enterprise Audit Log
+### Audit Log
 - Persistent audit trail with SQLite storage and HMAC signing.
 - Queryable via `/api/audit` and verified per event in the Security → Audit Log UI.
 - Supports filtering, verification badges, and signature checks for tamper detection.