💡 Support batch voting submission for multiple governance actions

### Area

Voting Pillar

### Is there new design needed?

Yes

### What?

Introduce the ability for users to submit votes on multiple governance actions in a single transaction, rather than requiring separate submissions for each.

### Why?

Currently, users must vote on governance actions one by one, which becomes time-consuming and tedious when there are many proposals active at once. This inefficiency can lead to lower participation rates. Batch voting streamlines the process, improving the user experience and making participation more practical and scalable.

### How?

- Implement a "batch voting" mode where users can add votes to a pending submission list.
- Each vote includes choice (Yes/No/Abstain) and optional rationale.
- Provide a UI to manage the batch: view, edit, remove, and reorder votes before submission.
- On confirmation, submit all votes in a single on-chain transaction.
- Maintain support for the existing individual voting flow as an alternative.

### (Optional) User Story with acceptance criteria

As an active voter,
I want to add multiple votes across different governance actions to a batch,
So that I can review and submit them all in a single transaction.

#### Acceptance Criteria
- [ ] Users can toggle batch voting mode on/off
- [ ] Each governance action has an option to “Add to Batch”
- [ ] Batch includes governance action reference, vote choice, and rationale
- [ ] Users can edit or remove items from the batch before submission
- [ ] Batch voting is submitted as one transaction
- [ ] Standard voting flow remains available for individual voting