Feat: Add automated balance checking and message lifecycle management

[amalcaraz]

Self proofreading checklist

• Is my code clear enough and well documented
• Are my files well typed
• New translations have been added or updated if new strings have been introduced in the frontend
• Database migrations file are included
• Are there enough tests
• Documentation has been included (for new feature)

Changes

• Implements automated balance checking cron job that monitors account balances and manages message storage lifecycle based on funding status
• Adds grace period mechanism for message removal and recovery, with comprehensive database migrations and test coverage

How to test

• Verify database migrations apply correctly
• Test balance job marks messages for removal when balance insufficient
• Test messages below cutoff height are ignored
• Test message recovery when balance becomes sufficient
• Verify grace period file pins are created/updated correctly
• Test cron job scheduling and execution
• Run existing test suite to ensure no regressions