MCP Python SDK v1.29.0：新增请求体限制与工具名校验修复

What's Changed

• [v1.x] Route Context.report_progress() to the originating request stream by @maxisbey in #2994
• [v1.x] docs: publish llms.txt and markdown renditions of the docs by @maxisbey in #3029
• [v1.x] docs: pin mkdocs<2 by @maxisbey in #3074
• [v1.x] Add Streamable HTTP request body limits by @Kludex in #3101
• [v1.x] fix: reject trailing newline in tool-name validation by @maxisbey in #3086
• [v1.x] ci: pick the docs toolchain per worktree in build-docs.sh by @maxisbey in #3082
• [v1.x] Move the v1.x docs to /v1/ and mark v1.x as the maintenance line by @maxisbey in #3177

Full Changelog: v1.28.1...v1.29.0