Automated Petition Expiry & Reminders (Watcher Service)

Description Implement a background Cron Job ("Smart Watcher") to manage stale petitions.

**Technical Implementation:**

Schema: Create a Petition_Monitors table (FK to petitions) to store
stage_entered_at and reminder_count(how many times email has been sent) Whenever the status of the petition is changed the table of Petiton_Monitor will be reset.

Cron Job: Runs hourly or after every 5 hours or once per day to either inform the user or delete petition.
In consts.py we will write the rules for every status -> how many times user should be informed at this stage. i.e When approver asks for a revision and supervisor hasn't done the changes he should be informed more times before deleting the petition instead of a student.
We will control the number of times the user is informed from consts.py so we can change it later. If the threshold is met petition will be deleted by the watcher and everyone will be informed about this.