fix: use `abi.encode` for hashing arrays (XMTP-10) (#165)

Change hashing of nodeIds_ to use abi.encode in PayerReportManager to address XMTP-10
This pull request updates the hashing logic in the PayerReportManager contract to use abi.encode for nodeIds_ when computing the keccak256 that combines endSequenceId_, endMinuteSinceEpoch_, payersMerkleRoot_, and the nodeIds_ hash. It also updates unit tests to reflect the new computed values.

Modify PayerReportManager to replace abi.encodePacked(nodeIds_) with abi.encode(nodeIds_) in the hash computation in PayerReportManager.sol
Update three expected bytes32 constants in tests to match the new hash results in PayerReportManager.t.sol

Store endMinuteSinceEpoch as part of PayerReport (#110)

### Store endMinuteSinceEpoch as part of PayerReport struct in
settlement-chain contracts
- Adds `endMinuteSinceEpoch` field to the `PayerReport` struct in
[IPayerReportManager.sol](https://github.com/xmtp/smart-contracts/pull/110/files#diff-9fb0d383a957303659dfce9466a61de006a70c84e9d00bcc77e77d2cb559dd16)
to track the timestamp of the message at `endSequenceId`
- Updates `PayerReportManager.sol` contract to include the new
`endMinuteSinceEpoch_` parameter when creating `PayerReport` objects in
[PayerReportManager.sol](https://github.com/xmtp/smart-contracts/pull/110/files#diff-6a7edafdcbfd59cce9a879b0794c842ebd8f7eb961fa871b85f25513232a82f9)
- Modifies test files to pass the new `endMinuteSinceEpoch_` parameter
with value 0 in
[PayerReportManager.t.sol](https://github.com/xmtp/smart-contracts/pull/110/files#diff-88d841009e835b92dfaa91cbaaca83627d59bcb7e62090ff6a6af09f7ee67bdb)
and
[Harnesses.sol](https://github.com/xmtp/smart-contracts/pull/110/files#diff-f803a3747dfd9bb6151512e75424166315fd4e6c591066540f3f690ec7093177)

#### 📍Where to Start
Start with the `PayerReport` struct definition in
[IPayerReportManager.sol](https://github.com/xmtp/smart-contracts/pull/110/files#diff-9fb0d383a957303659dfce9466a61de006a70c84e9d00bcc77e77d2cb559dd16)
to understand the new field addition, then review how it's used in the
contract implementation in
[PayerReportManager.sol](https://github.com/xmtp/smart-contracts/pull/110/files#diff-6a7edafdcbfd59cce9a879b0794c842ebd8f7eb961fa871b85f25513232a82f9).

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_[Macroscope](https://app.macroscope.com) summarized bdc4b6c._

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **New Features**
* Added a new timestamp field to payer reports, capturing the time
associated with the end of a report period.

* **Bug Fixes**
* Ensured the new timestamp field is properly initialized when creating
payer reports.

* **Tests**
* Updated tests to include and validate the new timestamp field in all
relevant scenarios.

* **Documentation**
* Improved comments and field naming for clarity in payer report
structures.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

- testnet-dev (full v0.5.0 protocol)

- mainnet Base (minimal settlement chain v0.5.0 contracts)

Release v0.4.1

Run CI on branch and main (#83)

### Expand GitHub workflow to run CI on branch and main pushes in
addition to tag events
The GitHub workflow
[.github/workflows/release-from-tag.yml](https://github.com/xmtp/smart-contracts/pull/83/files#diff-cee4eadd46d2585fd337f530116877504920be9ec452bdbfb915b95857438208)
now triggers on pushes to the `main` branch and pull requests in
addition to tag events. The workflow adds multiple Docker image tagging
strategies including `type=ref,event=branch`, `type=ref,event=pr`, and
`type=sha` for different event types, while restricting semver tagging
to tag events only. Build artifacts are uploaded for all workflow runs
using `actions/upload-artifact@v4`, and GitHub Release creation is made
conditional with `if: startsWith(github.ref, 'refs/tags/')` to only
occur for tag events.

#### 📍Where to Start
Start with the workflow trigger configuration at the top of
[.github/workflows/release-from-tag.yml](https://github.com/xmtp/smart-contracts/pull/83/files#diff-cee4eadd46d2585fd337f530116877504920be9ec452bdbfb915b95857438208)
to understand the new event conditions.

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_[Macroscope](https://app.macroscope.com) summarized e69c9e1._