Add unit test suite for AnalyticsModule

[Code-Paragon]

Problem

There are no tests verifying that the AnalyticsModule correctly fetches and parses the Total Value Locked (TVL) from the Soroban RPC.

Expected behavior

A new test file analytics.test.ts is created that mocks the Stellar RPC response and verifies that getTVL returns the correct human-readable decimal string.

Files to update

• tests/analytics.test.ts (create)

Project relevance

Ensures that the primary metrics module functions correctly without requiring a live connection to the Stellar testnet during CI runs.

Acceptance criteria

• Feature works as described
• Tests are added or updated where needed
• Documentation is updated where needed
• this.client.rpcServer.simulateTransaction is mocked using Jest to return a mock XDR payload
• No TypeScript, lint, test, or build errors