Spike] Profile Soroban Instance vs Persistent DataKey Storage Rent & TTL Expiration Strategy

[Darkvader-ship-it]

Estimated Effort: 2 weeks / 8 days

Impacted Subsystems / Files:

• contracts/phase-protocol/src/lib.rs
• scripts/deploy-phase-sep50.ts

Context & Problem Statement:
Soroban ledger entries require active TTL rent bumps to avoid archiving. The contract in contracts/phase-protocol/src/lib.rs mixes instance storage with persistent storage across UserPhase, TokenOwner, and Collection data keys without automated bump logic, risking protocol lockout if storage entries expire.

Technical Requirements & Scope:

1. Profile storage rent costs for all DataKey variants over 100,000 ledgers.
2. Implement automated env.storage().persistent().extend_ttl() invocations inside high-frequency functions (settle, initiate_phase, transfer).
3. Create a standalone TypeScript utility script in scripts/extend-protocol-ttl.ts that scans and extends storage TTLs for all protocol state entries.
4. Document storage rent budgeting guidelines for protocol maintainers.

Multi-File Change Surface:
Touches contracts/phase-protocol/src/lib.rs storage invocation paths and adds deployment maintenance tooling under scripts/.

Acceptance Criteria:

• All persistent contract keys automatically maintain minimum 30-day TTL buffer.
• Script scripts/extend-protocol-ttl.ts executes successfully against testnet without hitting fee limits.

Suggested Approach / Investigation Steps:

1. Simulate 6-month ledger advancement using Soroban test environment.
2. Add extend_ttl calls inside contracts/phase-protocol/src/lib.rs.
3. Validate TTL extension behavior using Stellar Expert explorer.

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