release notes and change logs for 2.70

[dannimad]

pnpm flub generate releaseNotes -g client -t minor --outFile RELEASE_NOTES/2.70.0.md
pnpm flub generate changelog -g client

[Copilot]

Pull Request Overview

This PR adds release notes and changelogs for version 2.70.0, generated using automated tools. The release includes breaking changes, new features, and SharedTree DDS improvements.

Key changes:

• Breaking changes removing deprecated APIs across multiple packages
• New beta APIs promoted from alpha in devtools and SharedTree
• Updated changelog files across all packages to document version 2.70.0

Reviewed Changes

Copilot reviewed 175 out of 175 changed files in this pull request and generated no comments.

File	Description
RELEASE_NOTES/2.70.0.md	Comprehensive release notes documenting breaking changes, new features, and deprecations
Multiple CHANGELOG.md files	Version 2.70.0 changelog entries added across all affected packages
.changeset/*.md files	Changeset files removed after being processed into changelogs

[github-actions]

🔗 Found some broken links! 💔

Run a link check locally to find them. See
https://github.com/microsoft/FluidFramework/wiki/Checking-for-broken-links-in-the-documentation for more information.

linkcheck output

> [email protected] ci:check-links /home/runner/work/FluidFramework/FluidFramework/docs
> start-server-and-test "npm run serve -- --no-open" 3000 check-links

1: starting server using command "npm run serve -- --no-open"
and when url "[ 'http://127.0.0.1:3000' ]" is responding with HTTP status code 200
running tests using command "npm run check-links"


> [email protected] serve
> docusaurus serve --no-open

[SUCCESS] Serving "build" directory at: http://localhost:3000/

> [email protected] check-links
> linkcheck http://localhost:3000 --skip-file skipped-urls.txt

 ELIFECYCLE  Command failed with exit code 1.