fix(microsoft-foundry): vnet

[swatDong]

Description

Sync latest foundry private network sub skill.

• remove the "preview" tag/suffix and feature flag
• update to latest links and templates
• update post-deploy step

Checklist

• Tests pass locally (cd tests && npm test)
• Title has one of the prefixes: fix:, feat:, feature:, chore:, misc:, test:, eval:
• If modifying skill descriptions: verified routing correctness with integration tests (In tests/, npm run test:integration -- <skill> or npm run test:vally -- --skill <skill>)

[Copilot]

Pull request overview

This PR syncs the microsoft-foundry/private-network guidance with the latest Foundry private networking templates and documentation, aiming to remove “preview” labeling/feature-flag guidance and update post-deploy steps.

Changes:

• Updated Learn documentation links from legacy azure/ai-foundry paths to current azure/foundry equivalents.
• Removed Managed VNet “preview” wording and feature-flag registration guidance from intake/preflight content.
• Added Managed VNet post-deployment guidance and validation checks around outbound private endpoint rules (including a self-referencing PE).

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
plugin/skills/microsoft-foundry/resource/private-network/references/template-index.md	Adds a link to deployment helper scripts and updates example template folder naming (drops “preview” suffix).
plugin/skills/microsoft-foundry/resource/private-network/references/post-deployment-validation.md	Adds a Managed VNet outbound rules validation step via az rest.
plugin/skills/microsoft-foundry/resource/private-network/references/intake.md	Removes preview/feature-flag intake items, adds AI Search auth constraint guidance, and refreshes Learn links.
plugin/skills/microsoft-foundry/resource/private-network/references/deploy.md	Adds a Managed VNet required post-deploy note and refines retry guidance for legionservicelink.
plugin/skills/microsoft-foundry/resource/private-network/private-network.md	Refreshes key documentation links and updates preflight provider registration guidance + retry rule wording.

[jongio]

The eval CI check is failing. Worth verifying it isn't related to these content changes.

One structural suggestion on the new post-deploy section in deploy.md.

[swatDong]

The eval CI check is failing. Worth verifying it isn't related to these content changes.

One structural suggestion on the new post-deploy section in deploy.md.

comment addressed. the failed eval CI is about other skill (azure-compute) unrelated to this PR.

[jongio]

The eval CI failure traces to azure-compute, not this PR (all foundry/private-network checks pass). No further concerns on the incremental changes or the full diff.