Fix proposal vote percentage calculation

[shashankvaishnav]

Closes #184.

This updates the vote percentage calculation to sum the available vote_count rows instead of assuming all three vote types are present. Older proposals can omit vote types with zero weight, which caused proposal #1 to fail when the UI accessed a missing array entry.

Validation:

• git diff --check
• npm run lint (fails locally because dependencies are not installed: eslint not found)

[shashankvaishnav]

Hi maintainers, I opened this PR for #184.

The fix avoids assuming all three vote_count entries exist and instead sums the vote_count rows returned by the chain table. This should handle older proposals like proposal #1 where zero-value vote types were not stored.

Could you review when you have time?