refactor: rename all secret scanner internals to auto-redact

Full internal rename since still in testing — no backwards compat needed:
- secret-scanner.js → auto-redact.js
- SecretScanner → AutoRedact
- SECRET_PATTERNS → REDACT_PATTERNS
- secretScanning → autoRedact (setting key)
- customSecretPatterns → customRedactPatterns (setting key)
- scanAndRedactSecrets → runAutoRedact (function)
- All DOM ids, CSS classes, and variable names updated
- category: 'secret' → category: 'redact'
- getOrgSecretPatterns → getOrgRedactPatterns

https://claude.ai/code/session_01KF4i7Ra7zCEDskxDBaNtcT

src/lib/storage.js

@@ -34,13 +34,13 @@ const DEFAULT_SETTINGS = {
   enabled: true,
   showHighlights: false,
   revealMode: false,
-  secretScanning: true,
+  autoRedact: true,
   autoDetect: true,
   autoRedactDetected: true,
   autoAddDetected: true,
   maxLogEntries: 100,
   customDomains: [],
-  customSecretPatterns: [],
+  customRedactPatterns: [],
   categories: ['name', 'email', 'phone', 'address', 'ssn', 'dob', 'domain', 'password', 'general'],
   browserSync: false,
 };