Adds first-class Xiaomi Token Plan provider support with regional onboarding/configuration, token-plan key prefix validation, runtime pricing/catalog metadata, and docs/test coverage.
Keeps Token Plan model catalog discovery runtime-owned so region-specific base URLs are required and the provider cannot silently fall back to the static SGP manifest catalog.
Fixes#86169.
Verification:
- node scripts/run-vitest.mjs src/plugins/provider-discovery.runtime.test.ts extensions/xiaomi/index.test.ts src/plugins/manifest-model-catalog.test.ts src/model-catalog/manifest-planner.test.ts
- git diff --check
- autoreview --mode local: clean, no accepted/actionable findings
- CI run 26678998539: all relevant checks passed; check-prod-types failed on unrelated browser unused-function issue already present on origin/main
Co-authored-by: NianJiuZst <3235467914@qq.com>
Co-authored-by: Peter Steinberger <steipete@gmail.com>
