feat: resolve issues #294, #308, #295, #297

[serverlessdomain-hash]

Closes #294
Closes #308
Closes #295
Closes #297

Summary of Changes

1. Reputation-registry storage unchecked overflow in increment functions (#294)

• Fix: Replaced plain + 1 arithmetic with saturating_add(1) in increment_streak, increment_completions, and increment_defaults within packages/reputation-registry/src/storage.rs.
• Impact: Prevents storage counters from overflowing and wrapping/panicking under high volume or extreme values.

2. Staking UNBONDING_PERIOD_SECONDS getter and usage clarity (#308)

• Fix: Added public getter function get_unbonding_period_seconds(&Env) -> u64 in packages/staking/src/contract.rs and exposed get_unbonding_period_seconds(Env) -> u64 on the Staking contract interface in packages/staking/src/lib.rs.
• Impact: Exposes the 14-day unbonding period duration constant (1,209,600 seconds) to external callers and frontends.

3. Reputation-registry negative payment amount cast protection (#295)

• Fix: Added input validation assert!(amount >= 0, "amount must be non-negative"); and defensive bounds handling let safe_amount = amount.max(0); in record_on_time_payment in packages/reputation-registry/src/scoring.rs.
• Impact: Prevents negative amount parameters from being cast to u32 and producing unexpectedly high volume bonuses.

4. Escrow-swap storage refactoring to Map for O(1) performance (#297)

• Fix: Refactored DataKey::SwapRequests storage from Vec<SwapRequest> to Map<u64, SwapRequest> in packages/escrow-swap/src/contract.rs. Updated create_swap, accept_swap, complete_swap, cancel_swap, and get_swap to use direct O(1) key lookups and writes, while get_swaps() efficiently returns swaps.values().
• Impact: Eliminates O(n) iteration across swap lists, preventing scale degradation and high gas fees as swap counts grow.

Testing & Verification

• Unit test suites added for saturating arithmetic in reputation storage, negative amount validation in scoring, and get_unbonding_period_seconds in staking.
• Full test suites executed across all modified packages (reputation-registry, staking, escrow-swap) with all 51 tests passing cleanly.

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[cypriannwokolo2-creator]

This PR (and its peer master state) has merge conflicts in packages/{escrow-swap,reputation-registry,staking}. While reviewing I also found the current master staking package does not compile (pre-existing duplicate get_stake_amount/get_all_stakers and an undefined StakersList), separate from your changes. Could you rebase onto latest master and re-run the staking/reputation-registry tests? Happy to merge once it's green.