feat(sdk): add governance SDK view methods

[Junman140]

Closes #427

Description

Adds SDK wrapper methods for the governance contract view functions that the SDK was missing:

• \getDelegate(server, contractAddress, addr, sourceAccount, networkPassphrase)\ → \string | null\ — direct delegate for an address
• \getMinQuorumBps(server, contractAddress, sourceAccount, networkPassphrase)\ →
  umber\ — minimum quorum in basis points
• \getMinProposalBalance(server, contractAddress, sourceAccount, networkPassphrase)\ → \�igint\ — minimum token balance to submit proposals
• \getExecutionDelay(server, contractAddress, sourceAccount, networkPassphrase)\ →
  umber\ — execution delay in ledgers
• \isVetoPowerEnabled(server, contractAddress, sourceAccount, networkPassphrase)\ → \�oolean\ — whether admin veto is active

Changes

• \sdk/src/methods/governance.ts: Added 5 new view methods and a shared \simulateView\ helper
• \sdk/src/methods/governance.test.ts: Added 7 test cases for new methods
• \sdk/src/index.ts: Exported the new methods

[Levi-Ojukwu]

@Junman140 please resolve the conflict