Add a new section for Windows Server 2016 to 2022 in-place upgrade, mirroring the existing 2016→2019 guide structure.

## Motivation

- Windows Server 2016 reaches end of support in January 2027
- Customers may want to skip 2019 and go directly to 2022 (Microsoft supports this two-version jump via installation media)
- Windows Server 2022 offers longer support runway (mainstream support through October 2026, extended through October 2031)
- The existing 2016→2019 SSM automation can be adapted with minimal changes for a 2022 target

## What's Included

- **SSM Automation Documents:**
- `Windows-2016-to-2022-Upgrade.json` (65 steps, adapted from 2016→2019)
- `windows-2016-to-2022-precheck.json` (11 steps)
- **Documentation:**
- Upgrade Guide (with both AWS CLI and PowerShell commands)
- IAM Roles Setup
- Automation Flowchart
- **Key differences from 2016→2019:**
- Targets `Windows 2022 {lang} Installation Media` snapshots
- Verifies OS build 20348.x (Server 2022)
- .NET 4.8 in-box (vs 4.7.2 on 2019)
- Pinned CUs target Server 2022

## Testing

- Tested successfully on t3.large (us-east-1)
- Source: Windows Server 2016 Base AMI (license-included)
- Result: Windows Server 2022 Datacenter, build 20348
- All 65 automation steps passed
- Total upgrade time: ~37 minutes

## Microsoft Reference

[Plan your Windows Server upgrade](https://learn.microsoft.com/en-us/windows-server/get-started/install-upgrade-migrate?tabs=media) confirms 2016→2022 is a supported in-place upgrade path via installation media.

## TODO before merge

- [ ] Replace placeholder CU URLs with real Server 2022 June 2026 cumulative update URLs
- [ ] Verify 2022 installation media snapshots exist in all target regions
- [ ] Add IAM Roles Setup page (adapt from 2019 version)
- [ ] Add Automation Flowchart (adapt from 2019 version)

Start by comparing Windows-2016-to-2022-Upgrade.json and windows-2016-to-2022-precheck.json with the existing 2016→2019 automation, then review the Upgrade Guide and related 2019 IAM Roles Setup and Automation Flowchart materials. Verify the Server 2022 CU URLs and installation-media snapshots across target regions. Done means the documents, guide, IAM page, and flowchart are complete and the 65-step automation succeeds on the stated test setup.

Written by the indexing model from the issue text.