Add end-to-end smoke test covering all new dashboard endpoints in scripts/smoke-test.sh

[christabel888]

Context: scripts/smoke-test.sh already exists for post-deploy verification -- this batch adds ~15 new endpoints that should be covered before this ships.

Where:

• scripts/smoke-test.sh

What to do:

• Add a curl/check for each new endpoint from Add /api/v1/stats/summary endpoint: DAA, tx count 24h, payment volume 24h, active soroban contracts #1, Add /api/v1/assets/{code}/insights endpoint #11-Add governance insights endpoint: proposal momentum, voter turnout #14, Add /api/v1/network/daily-active-accounts time-series endpoint #15-Add /api/v1/network/fee-trends endpoint #19, Add /api/v1/soroban/active-contracts endpoint #21-Add /api/v1/soroban/top-contracts and /new-deployments endpoints #24, Add /api/v1/wallets/{address}/portfolio endpoint #25-Add /api/v1/wallets/{address}/largest-transfers endpoint #29, Add /api/v1/rankings/top-movers endpoint: 24h percent change by holders/volume #33, Add /api/v1/rankings/assets endpoint: top assets by holders and volume #39 confirming a 200 and non-empty response.

Suggested approach:

1. Add one curl-based check per new endpoint to scripts/smoke-test.sh, following its existing format.
2. Run it against a real (staging/local) deployment, not just unit tests -- the point of a smoke test is catching wiring/deployment issues unit tests can't see.

Watch out for:

• This issue is naturally last in sequence -- most of Add /api/v1/stats/summary endpoint: DAA, tx count 24h, payment volume 24h, active soroban contracts #1-Add rate-limit tier for public analytics API consumers #41 need to exist before this is meaningfully completable. Don't start it too early or you'll be constantly rebasing against endpoints that don't exist yet.

Definition of done:

• scripts/smoke-test.sh checks every new dashboard endpoint