fix: remove personal emails, gitignore sensitive paths, untrack local settings

- Replace hardcoded personal email in clear-user-data.sql with placeholder
- Change SECURITY.md contact to role-based security@arcim.io
- Add supabase/.temp/ and .claude/settings.local.json to .gitignore
- Untrack .claude/settings.local.json (keeps file on disk)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

scripts/clear-user-data.sql

@@ -15,7 +15,7 @@
 DO $$
 DECLARE
   -- >>> SET THE TARGET USER EMAIL HERE <<<
-  target_email TEXT := 'jakob.wennberg@arcim.io';
+  target_email TEXT := 'user@example.com';  -- change this to the target user's email
   target_user_id UUID;
 BEGIN
   -- Resolve email to user ID