Add queuedDepositAmounts mapping to track and query deposit amounts for scripts

[liobrasil]

Problem

When a deposit exceeds the rate limit cap, the excess amount is queued for async processing—but there's currently no way to query these queued balances. This creates confusion about the whereabouts of user assets.

Example:
Position 1 deposited 500K FLOW, but our 5% deposit rate limit only allowed 50K to process immediately. The remaining 450K is safely queued and will auto-process via asyncUpdatePosition() — however, this balance was invisible when querying position details.

Solution

This PR adds:

• A queuedDepositAmounts mapping to track pending deposit balances
• A get_queued_deposits.cdc script to query these balances
• A syncQueuedDepositAmounts() function to handle legacy positions that had queued deposits before tracking was introduced

[liobrasil]

⚠️ Testing Limitations & Deployment Notes

What the tests cover

The integration test (queued_deposits_integration_test.cdc) validates:

• ✅ New deposits exceeding limit are queued correctly
• ✅ get_queued_deposits.cdc script returns correct values
• ✅ Partial async processing updates tracking correctly
• ✅ Full async processing removes tracking entries

What the tests do NOT cover

1. Legacy migration scenario - The test creates fresh positions where queuedDepositAmounts is tracked from the start. It does not simulate the production scenario where Position 1 has 450K FLOW in queuedDeposits but empty queuedDepositAmounts.

2. syncQueuedDepositAmounts function - The new sync function is not directly tested. Its logic was code-reviewed but should be validated on testnet before mainnet deployment.

3. Adding to existing queue - The else branch in the deposit path (adding to an existing queue) is not explicitly tested.

Production Deployment Steps

# 1. Deploy updated contract
flow project deploy --network mainnet

# 2. IMMEDIATELY sync Position 1 (and any other affected positions)
flow transactions send cadence/transactions/flow-credit-market/pool-management/sync_queued_deposit_amounts.cdc 1 --network mainnet --signer <protocol-account>

# 3. Verify
flow scripts execute cadence/scripts/flow-credit-market/get_queued_deposits.cdc 1 --network mainnet
# Expected: {Type<@FlowToken.Vault>(): 450000.0} (approximately)

⚠️ Important: Until the sync transaction is run, getQueuedDeposits(pid: 1) will return {} even though 450K FLOW exists in the queue.