Feat/dispute freeze effect

[OluRemiFour]

Close: #595

Here's a summary of what we accomplished:
Feature: Dispute freeze effect — halts claims for an offering while a critical dispute is open.
Pre-existing corruption fixes (merge artifacts):

1. src/test_storage_layout_version.rs — removed dangling function body, cleaned imports
2. 7 duplicate PauseState definitions — consolidated into one canonical version with #[repr(u32)] and Copy
3. Duplicate DataKey2 variants (SupplyCap, DepositedRevenue, InvestmentConstraints, MinRevenueThreshold) — removed duplicates
4. Duplicate mod test_close_period; — removed one
5. Error discriminant conflicts — MaxTotalSupplySharesExceeded = 51 → 67, FaucetCooldownActive = 56 → 65
6. symbol_short! length violations — vest_accel → vst_accl, dsp_frzoff → dsp_fzoff
   8 edge case tests added to src/test_dispute.rs covering: multiple simultaneous critical disputes, freeze on/off events, rejected resolutions still clearing freeze, freeze isolation across offerings, and standard disputes not emitting freeze events.
   Known blocker (pre-existing): #[contracterror] LengthExceedsMax — 63 RevoraError variants exceed Soroban SDK v21's ~32-variant limit. Affects both master and our branch — not caused by our changes.

[OluRemiFour]

Done, Close: #656