fix(reflection): recognize MiniMax regional endpoint and align provider id

[octo-patch]

Reason: MiniMax reflection provider inference ignored the regional api.minimaxi.com endpoint and returned a provider id inconsistent with the explicit model-reference path, making bare-name configuration region-dependent.

What changed

• inferProviderFromBaseURL now recognizes both MiniMax base URLs — api.minimax.io (global) and api.minimaxi.com (regional) — using the existing "." + suffix endsWith guard that blocks host spoofing (e.g. fake-minimax.io, fake-minimaxi.com).
• It now returns the minimax provider id, matching the id parsed from an explicit minimax/<model> reference in splitProviderModel, so a bare model name such as MiniMax-M3 or MiniMax-M2.7 resolves to the same provider regardless of the configured region.

Why

The global host previously mapped to minimax-portal while the explicit model-reference path used minimax, and the regional host was not matched at all. Bare-name reflection configuration was therefore region-dependent and inconsistent between the two resolution branches (split.provider ?? inferProviderFromBaseURL(...)).

Tests

• Extended test/infer-provider-from-baseurl.test.mjs with the updated provider id, both regional hosts (/v1 and /anthropic base URLs), and fake-minimaxi.com spoofing protection.
• node --test test/infer-provider-from-baseurl.test.mjs — 13/13 pass.
• npx tsc -p tsconfig.json --noEmit — passes.

[rwmjhb]

Reviewed head 43a9711. The source-level targeted tests and full suite pass, but the published runtime does not contain this fix.

index.ts now recognizes .minimaxi.com and returns minimax, while the tracked dist/index.js at this same head still recognizes only .minimax.io and returns minimax-portal. package.json.main points installed plugins at dist/index.js, and this PR changes only index.ts plus the source-oriented test. As submitted, repository tests pass but installed/published users continue executing the old behavior.

Please run the project build, commit the resulting dist/index.js, and run npm run verify-package-runtime (or the equivalent package dry-run) so the generated delivery artifact is verified. A focused packaged-runtime assertion for both MiniMax hostnames would prevent this source/dist split from recurring.

Non-blocking compatibility follow-up: the existing .minimax.io return value changes from minimax-portal to minimax; an end-to-end provider consumer test would make that intentional contract change safer than helper-only expectations.