`block.timestamp` Returns Incorrect Value

## Summary
The EVM opcode block.timestamp returns the timestamp of a previous block instead of the current block's `firstConsTimeOfCurrentBlock`. This causes smart contracts to see an incorrect (earlier) timestamp, which can affect time-sensitive DeFi protocols, auctions, and other time-dependent contract logic.

## Environment
- Networks affected: Testnet (confirmed), Mainnet (reported)

### Reproduction Steps
1. Deploy a simple contract that captures `block.timestamp`:
```
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract BlockTimestampTest {
event TimestampCaptured(uint256 blockTimestamp, uint256 blockNumber);

function captureTimestamp() external returns (uint256) {
emit TimestampCaptured(block.timestamp, block.number);
return block.timestamp;
}
}
```
2. Call `captureTimestamp()` when your transaction is not the first transaction in the block
3. Compare the emitted `block.timestamp` with the block's actual timestamp from Mirror Node API

## Evidence
### Test Case 1
Block info from Mirror Node:
```
{
"number": 28624019,
"timestamp": {
"from": "1765294936.048991000",
"to": "1765294937.954070000"
}
}
```
First transaction in block:
- Consensus timestamp: `1765294936.048991000`
- Type: `CONSENSUSSUBMITMESSAGE (non-EVM)`

Contract's block.timestamp: `1765294935`

| Expected | Actual | Difference |
|------------|------------|------------|
| 1765294936 | 1765294935 | -1 second |

### Test Case 2
Block info from Mirror Node:
```
{
"number": 28625089,
"timestamp": {
"from": "1765297076.004691853",
"to": "1765297077.941060000"
}
}
```
Contract's block.timestamp: 1765297074

| Expected | Actual | Difference |
|------------|------------|------------|
| 1765297076 | 1765297074 | -2 seconds |

## Expected Behavior
`block.timestamp` should return `firstConsTimeOfCurrentBlock.seconds()` where `firstConsTimeOfCurrentBlock` is the consensus timestamp of the first transaction in the current block.

For block 28624019:
- First transaction: 1765294936.048991000
- Expected block.timestamp: 1765294936

## Actual Behavior

`block.timestamp` returns the `firstConsTimeOfCurrentBlock` from a previous block, resulting in a timestamp 1-2 seconds earlier than expected.

## Additional Context

- The issue is reproducible and affects both testnet and mainnet
- The discrepancy is not consistent (sometimes 1 second, sometimes 2 seconds behind)

Start by tracing the EVM implementation of block.timestamp and its use of firstConsTimeOfCurrentBlock, then compare that value with the Mirror Node API data for the supplied block numbers. Done means the opcode returns the current block's first consensus timestamp for transactions that are not first in the block, matching the reproduction contract's expected result.

Written by the indexing model from the issue text.