Enable Cosmos Module Events to be Indexed by EVM Indexers

## Problem

Currently, when Cosmos SDK modules emit events, these events are not visible to EVM-side indexers and explorers because they don't emit `EventTypeEthereumTx` events. This creates a tracking gap for important state changes that involve fund movements.

### Examples

**Staking Module:**
- When unbonding occurs, funds are transferred but the transaction is not trackable in EVM explorers
- When rewards are claimed, the fund movement is invisible to EVM indexers

**Impact:** Users and applications relying on EVM explorers (Etherscan-like tools) cannot track these important transactions, leading to incomplete transaction history.

Start by tracing how Cosmos SDK module events for staking unbonding and reward claims are emitted, then compare them with the EventTypeEthereumTx events consumed by EVM indexers. Done means those fund movements are visible and trackable in EVM explorers, with coverage for the stated staking cases.

Written by the indexing model from the issue text.