Expose AppInstallManager update requests by package family

Parent: #232

Dependencies and access restriction

Depends on #233, #234, #236. Implementation remains blocked until the supported-access gate and listed prerequisites are complete.

Microsoft documents AppInstallManager access as protected by a private capability restricted to Microsoft-developed apps. Do not bypass that restriction or treat runFullTrust/admin access alone as sufficient.

API scope

UpdateAppByPackageFamilyNameAsync and UpdateAppByPackageFamilyNameForUserAsync.

Acceptance criteria

• Accept an exact package-family identity and explicit current/specified-user scope, including typed pipeline identity where appropriate.
• Keep package-family names distinct from product IDs and display names. No wildcard expansion into unintended updates.
• Confirm each update request with ShouldProcess; preview submits nothing.
• Expose supported correlation inputs and capability/version gates without fabricating defaults.
• Return typed request/item information and preserve native failure, no-applicable-update and partial batch outcomes. Request acceptance does not establish an installed-version change.
• Reuse the shared monitoring and error contracts; do not duplicate the WinRT execution bridge.

Shared delivery requirements

Follow the parent epic's compiled-C# contract, user-scope and capability/version gates. Include deterministic Pester 6.2+ coverage, comment-based help, public documentation and unreleased notes in the same implementation PR. Use fail-closed fake adapters for side effects; no real installs, entitlement grants or settings changes in CI. Preserve original errors and distinguish unavailable, unknown, requested and completed outcomes.

Documented API references

• https://learn.microsoft.com/uwp/api/windows.applicationmodel.store.preview.installcontrol.appinstallmanager.updateappbypackagefamilynameasync
• https://learn.microsoft.com/uwp/api/windows.applicationmodel.store.preview.installcontrol.appinstallmanager.updateappbypackagefamilynameforuserasync

Begin with parent #232 and dependencies #233, #234, and #236; review the compiled-C# contract and the two AppInstallManager methods named in the issue. Then trace the shared monitoring and error contracts and fail-closed fake adapters, and use the required Pester 6.2+ coverage, documentation, and unreleased notes to verify the stated outcomes without real installs.