feat(sdk): type Router matched-market pair methods

[AntonsBB]

Summary

• add the missing matched-market pair parameter/result models to both SDKs
• add typed Router.fetchMatchedMarkets / fetch_matched_markets overrides and deprecated matched-price aliases
• parse nested markets into each SDK's public UnifiedMarket model and export the Python types at package root
• add focused transport, conversion, alias, and surface-regression coverage

Validation

• TypeScript strict compile: tsc --noEmit -p sdks/typescript/tsconfig.json
• TypeScript: 17 suites, 95 tests passed
• Python focused: 8 passed
• Python full non-integration suite: 270 passed, 66 deselected
• git diff --check

Closes #1819