fix: Generate correct bcrypt hash and update PostgreSQL admin password

- Create src/bin directory for temporary tools
- Generate correct bcrypt hash (60 chars) for 'admin123'
- Update PostgreSQL admins.password (clear corrupted data)
- Reinitialize auth.sqlite with complete table structure
- Verify admin login working with correct password

Key fixes:
- PostgreSQL admins.password: varchar(255) accepts 60-char bcrypt hash
- auth.sqlite sftpgo_admins: correct password_hash synced
- Admin login API: returns token + username
- Token verify API: returns ok=true

All tests passing:
✅ Admin sync: admins_synced=1
✅ Hash length: 60 chars (bcrypt standard)
✅ Admin login: success
✅ Token verify: success

Status: Admin authentication fully functional

src/bin/gen_hash.rs

@@ -0,0 +1,6 @@
+fn main() {
+    use bcrypt::{hash, DEFAULT_COST};
+    let password = std::env::args().nth(1).unwrap_or("admin123".to_string());
+    let hashed = hash(&password, DEFAULT_COST).unwrap();
+    println!("{}", hashed);
+}