test(integration): add rebalance protocol-path tests (#46)

[Mrwicks00]

Summary

Closes #46

Adds integration-level tests for all rebalance protocol-path transitions in the NeuroWealth Vault. These tests operate end-to-end using the existing mock/fixture pool (MockBlendPool, TestToken) to validate real on-chain fund movement, state changes, and emitted events.

Changes

• New file: contracts/vault/src/tests/test_rebalance_integration.rs — 13 integration tests
• Modified: contracts/vault/src/tests/mod.rs — registers the new test module

Tests Added

Test	Covers
test_integration_rebalance_to_blend_with_pool_configured	Happy-path: supplies all vault USDC to Blend, checks CurrentProtocol, asset accounting, and BlendSupplyEvent/RebalanceEvent
test_integration_rebalance_to_blend_already_in_blend_is_idempotent	Re-entrant blend→blend call does not duplicate supply
test_integration_rebalance_to_blend_without_pool_panics_with_balance	No pool + balance → explicit vault: blend pool not configured panic
test_integration_rebalance_to_blend_without_pool_panics_zero_balance	No pool + zero balance → same panic (pool check is unconditional)
test_integration_rebalance_from_blend_to_none_withdraws_all	Switches blend→none, withdraws all funds, validates BlendWithdrawEvent fields
test_integration_rebalance_none_to_none_is_noop	none→none leaves funds untouched, still emits RebalanceEvent
test_integration_full_protocol_round_trip	none→blend→none→blend end-to-end cycle
test_integration_rebalance_blend_zero_vault_balance_no_panic	Zero-balance blend call completes without panic; CurrentProtocol stays none (deterministic)
test_integration_rebalance_unknown_protocol_is_explicit_failure	Unknown protocol → vault: unsupported protocol
test_integration_rebalance_while_paused_explicit_failure	Paused vault → vault: paused
test_integration_asset_accounting_invariant_across_full_cycle	Two-user deposit → blend → partial withdraw → none; total assets conserved at every step
test_integration_rebalance_event_schema_correctness	Three rebalances emit exactly 3 events with correct protocol + expected_apy fields
test_integration_blend_supply_event_fields_are_correct	BlendSupplyEvent has correct asset, amount, success flag
test_integration_blend_withdraw_event_fields_on_protocol_switch	BlendWithdrawEvent has correct requested_amount, amount_received, success flag

Test Results

test result: ok. 175 passed; 0 failed; 0 ignored

Acceptance Criteria

• Integration tests run in CI (standard cargo test)
• All critical rebalance protocol transitions covered
• Failure-path assertions are explicit and deterministic
• CurrentProtocol, asset accounting, and rebalance events validated

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@Mrwicks00 Great news! 🎉 Based on an automated assessment of this PR, the linked Wave issue(s) no longer count against your application limits.

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