feat: Stellar Wave – Issues #252, #253, #254, #258

[DanielCharis1]

Summary

Implements all four Stellar Wave issues assigned to @DanielCharis1.

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Issue #258 – Auto-Rent-Deduction for Protocol Storage

• Adds a rent-deduction hook inside claim() that automatically deducts 1 000 stroops (0.0001 XLM) from the meter balance to extend the contract's ledger TTL.
• Only triggers when the current TTL falls below a 6-month safety threshold (~3 110 400 ledgers).
• Skips silently for non-XLM tokens to avoid blocking the stream.
• Emits a RentRenew event with the deduction amount and new TTL.
• Closes Implement "Auto-Renew" for Protocol Storage Rent #258

Issue #254 – Formal Proof: Per-Second Stream Exhaustion Invariant

• Adds calculate_remaining_balance() pure helper with floor-division rounding (always in favour of contract solvency).
• Adds 4 fuzz tests in fuzz_tests.rs:
  • test_stream_exhaustion_invariant_randomised – 100 000 randomised (balance, rate) pairs via deterministic LCG
  • test_stream_never_negative_after_pause_resume – 10-year simulation with pause/resume and partial top-ups
  • test_rounding_always_favours_solvency – verifies floor-division rounding direction
  • test_calculate_remaining_balance_never_negative – exhaustive grid search
• Creates SECURITY.md with a mathematical proof of the invariant and auditor documentation.
• Closes Formal Proof: Per-Second Stream Exhaustion Invariant #254

Issue #253 – Multi-Sig Technical Veto for IoT Fleet

• Adds FleetSecurityCouncil (up to 5 members, 3-of-5 threshold) and StagedFleetUpdate structs.
• New functions: register_fleet_council, stage_fleet_update, veto_fleet_update, execute_fleet_update, request_dao_council_rotation, finalize_dao_council_rotation.
• All fleet-level config changes go through a 48-hour staging window; the council can veto within the window.
• Emergency circuit-breaker updates bypass the staging window.
• Lost council keys can be rotated by the DAO after a 7-day delay.
• Emits FleetUpdateStaged, FleetUpdateVetoed, FleetUpdateExec events.
• Closes Implement Multi-Sig "Technical Veto" for IoT Fleet #253

Issue #252 – Built-In Dynamic Carbon-Credit Streaming

• Adds CarbonCreditState struct and CarbonCreditMinter cross-contract client interface.
• Hook in claim() accumulates credit slices: tokens_streamed × green_ratio × multiplier.
• Full integer credits trigger a cross-contract mint; failures are stored in a Deferred_Issuance buffer.
• New functions: set_green_energy_ratio, set_carbon_minter, retry_deferred_carbon_credits, get_carbon_credit_state.
• Emits CarbonCreditsAccrued and CCDeferred events.
• Closes Built-In Dynamic "Carbon-Credit" Streaming #252

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Bug Fixes (pre-existing)

• Removed duplicate use imports at top of lib.rs
• Added missing is_closed field to Meter struct
• Added missing green_energy_discount_bps and renewable_* fields in batch_register_meters
• Fixed broken refresh_activity(meter) call (missing now parameter)
• Removed duplicate get_provider_total_pool and get_watt_hours_display function definitions
• Fixed verify_usage_signature ? operator used in non-Result function
• Fixed get_effective_rate called with wrong arity in deduct_units

Testing

• 4 new fuzz tests in fuzz_tests.rs (Issue Formal Proof: Per-Second Stream Exhaustion Invariant #254)
• 6 new integration tests in test.rs covering Issues Built-In Dynamic "Carbon-Credit" Streaming #252, Implement Multi-Sig "Technical Veto" for IoT Fleet #253, Implement "Auto-Renew" for Protocol Storage Rent #258
• All tests run on every PR via .github/workflows/test.yml

[drips-wave]

@DanielCharis1 Great news! 🎉 Based on an automated assessment of this PR, the linked Wave issue(s) no longer count against your application limits.

You can now already apply to more issues while waiting for a review of this PR. Keep up the great work! 🚀

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