Start 2026.3 release cycle

[seanbudd]

Start the dev cycle for the 2026.3 release.
This won't be a compatibility breaking release.

Complete:

• New section in the change log.
• Update NVDA version in master
• Update nvdaAPIVersions.json to include the next version
  • Add NVDA 2026.3 API version information addon-datastore#9107
  • Re-run the last "Transform NVDA addons to views" on addon-datastore to regenerate projections (views) for the add-on datastore API.

On merge:

• Update auto milestone ID

[Copilot]

Pull request overview

Starts the NVDA 2026.3 development cycle by bumping the core version and adding a new, empty 2026.3 section at the top of the user-facing changelog.

Changes:

• Added a new “2026.3” section to user_docs/en/changes.md (with standard subsections) and moved the markdownlint-disable boundary so older sections remain excluded from linting.
• Updated source/buildVersion.py to set version_major = 3 (making the dev version string 2026.3.0dev).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
user_docs/en/changes.md	Introduces the 2026.3 changelog section and shifts the markdownlint disable marker to keep older sections unlinted.
source/buildVersion.py	Bumps the in-tree NVDA version major number to begin the 2026.3 dev cycle.