[WIP] Add optional Azure DevOps Wiki browser in VS Code

[Codex]

Thanks for asking me to work on this. I will get started on it and keep this PR's description up to date as I form a plan and make progress.

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This section details on the original issue you should resolve

<issue_title>Feature spec: optional Azure DevOps Wiki browser</issue_title>
<issue_description>## Summary
Evaluate and optionally add an Azure DevOps Wiki browser inside VS Code.

Product rationale

Wiki access can reduce context switching for project documentation, but it is less central to ADOExt than work items, PRs, builds, and planning. This should remain optional/low priority unless users explicitly want documentation browsing in the extension.

Proposed UX

Add a lightweight Wiki view only if it can stay focused and safe.

Tree view:

• Wikis by organization/project
• Page hierarchy
• Search/filter pages

Details panel:

• Rendered markdown page
• Last updated metadata
• Open in browser action

Suggested actions

• Open page in VS Code panel
• Open page in browser
• Copy page link
• Search wiki pages

Integration with existing core features

• Link wiki pages from work items/PR comments when URLs or wiki refs appear.
• Potentially add hover support for recognized wiki links later.

MVP scope

• Read-only wiki tree and markdown rendering.
• Open in browser.
• Basic search/filter.

Non-goals

• Editing wiki pages from VS Code.
• Complex markdown extensions beyond safe rendering.
• Replacing Azure DevOps documentation UX.

Security considerations

• Treat wiki markdown/content as untrusted.
• Sanitize rendered markdown.
• Keep CSP strict in the webview.

Acceptance criteria

• Wiki content renders safely in a webview.
• Missing permissions or missing wiki data produce a clear empty/read-only state.
• The feature does not add visual clutter to the default core workflow.
• npm run compile passes.
• npm run lint passes or reports only existing unrelated warnings.</issue_description>

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