State has a heartbeat

Most chains let state pile up forever — every node drags around every abandoned entry from 2019. Stellar refuses: every Soroban entry has a TTL (time-to-live), counted in ledgers, and rent extends it.

When the TTL runs out:

• Temporary entries are deleted. Gone.
• Persistent and instance entries are archived — evicted from the live ledger, but restorable later with a proof, returning exactly as they were.

This is state archival, and no other major chain does it. The live ledger stays lean, validators stay cheap, history stays recoverable.