Require login for crontab actions

[Aoody743]

Motivation

• The crontab blueprint exposed state-changing and execution endpoints (notably /modify_crond and /start_task) without authentication, enabling unauthenticated modification of cron scripts and remote code execution as the panel user.
• The change's intent is to block unauthenticated access to all sensitive crontab operations by enforcing the existing panel authentication decorator.

Description

• Added @panel_login_required to the crontab route handlers for logs, delete, delete-logs, set status, data list, get task, modify task, and start task in web/admin/crontab/__init__.py so these endpoints require authentication.
• Preserved existing functionality and existing authenticated routes (/index, /list, /add) while only adding the authentication guard to previously unprotected actions.
• No changes were made to crontab business logic beyond requiring authentication on the affected routes.

Testing

• Ran python -m py_compile web/admin/crontab/__init__.py which completed successfully and reported no syntax errors.
• Ran git diff --check which reported no whitespace or diff issues.

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Codex Task