feat: add GET /sponsors/funded-loans endpoint

[EmeditWeb]

Problem

Sponsors cannot see which loans their capital
is currently backing. This matters for
transparency and trust.

What To Build

Add GET /api/v1/sponsors/funded-loans endpoint.
Requires JWT auth.

Returns loans currently active that are backed
by the liquidity pool, with the sponsor share
percentage shown for each.

Response per loan:

• loan ID
• borrower wallet (truncated)
• vendor name
• amount
• installments paid/total
• status
• sponsor share percentage

Files To Touch

• src/modules/sponsors/sponsors.controller.ts
• src/modules/sponsors/sponsors.service.ts

Acceptance Criteria

• Returns only active loans
• Shows sponsor share per loan
• Paginated (default 10 per page)
• Full Swagger docs

Mandatory Checks Before PR

• npm run build passes
• PR references this issue

[Mmesolove]

Hi maintainer,I have read the description and I can resolve this issue, please kindly assign to me.