docs: broaden scope to Windows development and debugging

[rtrimceski-MS]

Description

Change the README heading to "Agents and skills for Windows development" and broaden the introduction to development and debugging across apps, services, and kernel-mode drivers.

Align the README contribution section and CONTRIBUTING.md inclusion criteria with that scope, and record the user-facing change under Unreleased in CHANGELOG.md.

This is documentation only: existing plugins, catalog entries, manifests, versions, pins, and installation instructions are unchanged. No service or kernel-mode debugging plugins are added by this PR.

Related Issue

None.

Type of Change

• 📝 Documentation

Checklist

• All three catalogs (.github/plugin, .claude-plugin, .agents/plugins) list the same plugins at the same pin
• Installed the plugin from this branch on each host and confirmed its skills load
• If user-facing: added a bullet to ## [Unreleased] in CHANGELOG.md

Additional Notes

Local validation was completed using Node v24.21.0 (meets the documented Node 22+ requirement):

Command	Result
node scripts/check-catalogs.mjs	Passed: both plugins resolve and match across all three catalogs.
npm ci --prefix scripts/vally --no-audit --no-fund	Passed: restored missing dependencies. npm warned about an unapproved koffi install script; no approval was granted.
node scripts/vally/lint-skills.mjs	Passed after dependency restoration: no local production plugins to lint. The initial attempt failed because vally was missing.
node scripts/tests/test-catalog-tools.mjs	Passed: all five fixture cases, including local-plugin lint and expected rejection cases.
git diff --check	Passed.

Outstanding before proposing merge:

• Complete the documented branch installation and skill-loading verification on each supported host. Not performed locally: only Copilot CLI was found, and existing host configuration was not changed.
• Confirm GitHub checks and any CLA requirement pass.
• Obtain catalog-maintainer review and approval of the expanded contribution scope. Default CODEOWNERS are Nikola Metulev (@nmetulev), Alexandre Zollinger Chohfi (@azchohfi), and Niels Laute (@niels9001).
• Obtain the author's review and explicit approval before merging.

Keep this PR in draft until the outstanding requirements are resolved. Do not enable auto-merge or merge before author approval.

AI Description

Expands the documented scope from Windows app development to Windows development and debugging across apps, services, and kernel-mode drivers. Updates README.md, CONTRIBUTING.md, and CHANGELOG.md only; existing plugin functionality and catalog pins remain unchanged.

[rtrimceski-MS]

@microsoft-github-policy-service agree company="Microsoft"