docs: add private packages guide and enhance authentication page

[Copilot]

Description

APM already supports private packages via git credentials, but the documentation had gaps: the Authentication page didn't explain how git credential helpers and git: object references work, and there was no dedicated guide for the private packages workflow.

This PR enhances the Authentication page to be the single source of truth for how APM authenticates, and adds a focused private packages guide that covers the workflow without duplicating auth details.

Authentication page (docs/src/content/docs/getting-started/authentication.md) — restructured with:

• New "How APM Authenticates" section explaining the three auth paths: token injection for GitHub/ADO, credential helper delegation for generic hosts
• Coverage of git: object references and how authentication applies to them
• GitLab, Bitbucket, and self-hosted git server support via SSH keys and git credential helpers
• Tighter "Token Reference" and "Common Setup Scenarios" sections

Private packages guide (docs/src/content/docs/guides/private-packages.md) — a concise workflow page (~70 lines) covering create → install → share → CI → org-wide, linking to Authentication for all auth details with no duplication.

Sidebar (docs/astro.config.mjs) — inserted "Private Packages" between Pack & Distribute and Org-Wide Packages.

Type of change

• Bug fix
• New feature
• Documentation
• Maintenance / refactor

Testing

• Tested locally
• All existing tests pass
• Added tests for new functionality (if applicable)

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[danielmeppiel]

@copilot this is not satisfactory - the Authentication page itself should speak about the case of an object reference to gitURL and how git credential helpers work there. Also, the guide seems to repeat a lot of stuff from the Authentication page. rethink the structure as a world class technical writer for developer tooling without bloating the docs.

[Copilot]

@copilot this is not satisfactory - the Authentication page itself should speak about the case of an object reference to gitURL and how git credential helpers work there. Also, the gui...

Restructured in 9f6840e. Two changes:

1. Authentication page now has a "How APM Authenticates" section that explains the three auth paths (token injection for GitHub/ADO, credential helper delegation for generic hosts), covers git: object references with examples, and documents GitLab/Bitbucket/self-hosted support.

2. Private packages guide is slimmed to a short workflow page (~70 lines) — create, install, share, CI. All auth details link back to Authentication, no duplication.

[Copilot]

Pull request overview

Documentation update to close gaps around how APM authenticates to private git repositories and to provide a dedicated, workflow-focused guide for private packages.

Changes:

• Added a new “Private Packages” guide describing the end-to-end workflow (create → install → share → CI).
• Restructured the Authentication page to explain APM’s auth paths (token injection vs git credential helpers/SSH) and object-style git: references.
• Updated the docs sidebar to include the new guide.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 9 comments.

File	Description
docs/src/content/docs/guides/private-packages.md	New workflow guide for creating and consuming private APM packages.
docs/src/content/docs/getting-started/authentication.md	Reorganized and expanded authentication documentation, including git: object references and setup scenarios.
docs/astro.config.mjs	Adds “Private Packages” to the Guides sidebar section.