ccxt v4.5.70：多语言性能优化与修复

What's Changed

• chore(docs): move playground/ and website/ under docs/ by @pcriadoperez in #29302
• perf(python): safeString optimization by @ttodua in #29315
• Update workflows by @frosty00 in #29326
• move to self-hosted github actions runners by @frosty00 in #29328
• github actions complains about old node20 versions by @frosty00 in #29330
• perf(go): safeString optimization by @ttodua in #29319
• fix(Exchange): omit paginationDirection in fetchPaginatedCallDeterministic by @g0rdonL in #29332
• fix(bitget): route UTA private WS order/fill to the right market by @slotheth in #29327
• fix(nado): parseMarkets in python by @carlosmiei in #29334
• perf(base): speed up pure-Python Keccak-256 fallback (~2x) by @pcriadoperez in #29318
• fix(client.py): add compress option (RFC 7692) by @carlosmiei in #29336
• perf(java): safeString optimization by @ttodua in #29320
• perf(c#): safeString optimization by @ttodua in #29316
• perf(php): safeString optimizations by @ttodua in #29314
• chore: temporarily try gh_token2 by @carlosmiei in #29337
• feat(nado): upgrade ws to v2 by @carlosmiei in #29338
• chore: pushback using github app by @carlosmiei in #29339
• chore: autostash in actions to avoid push error by @carlosmiei in #29340
• chore: disable cleanup old tags by @carlosmiei in #29341

Full Changelog: v4.5.69...v4.5.70