docs(suibets): remove deprecated events endpoint

[AbhilashG12]

Description

Fixes #1356.

Issue #1356 reported that the SuiBets GET /api/events/upcoming endpoint was returning a 400 Bad Request.

Upon auditing the runtime logic, I found that fetchRawEvents was already successfully refactored to synthesize events from /api/p2p/offers instead of using the broken endpoint. However, the legacy endpoint was left dangling in the api.ts documentation, leading to the open issue.

This PR simply removes the deprecated endpoint from the documentation to align it with the current implementation and safely closes the stale issue.

[realfishsam]

PR Review: PASS (NOT VERIFIED)

What This Does

Removes the deprecated GET /api/events/upcoming line from the SuiBets API reference comment. This does not affect runtime SDK behavior.

Blast Radius

Documentation-only comment in core/src/exchanges/suibets/api.ts; no exchange implementation, SDK, schema, or router code changes.

Consumer Verification

Before (base branch):
The comment listed GET /api/events/upcoming as a documented SuiBets endpoint, although the file explicitly has no runtime exports.

After (PR branch):
The stale endpoint line is removed. There is no consumer-visible API behavior to exercise because api.ts is documentation-only.

Test Results

• Build: PASS for current main core build during scheduled run
• Unit tests: PASS for current main core Jest (699 passed, 3 skipped)
• Server starts: NOT VERIFIED for this PR head
• E2E smoke: N/A (documentation-only)

Findings

No blocking findings.

PMXT Pipeline Check

• Field propagation (3-layer): N/A
• OpenAPI sync: N/A
• Financial precision: N/A
• Type safety: N/A
• Auth safety: N/A

Semver Impact

patch -- documentation/spec-comment cleanup only.

Risk

I did not perform an external SuiBets spec fetch; this review only verifies the PR is documentation-only in this repository.