Add a "Newly Added Packages" Feature to "winget source update" for Better Discoverability

Description of the new feature / enhancement

It would be great to have the winget source update have the ability to list completely new packages that were added to the Winget repository since the last update.

This isn't about updated or outdated versions of existing packages—this is about spotlighting brand-new entries that weren't there before.

The idea is simple: after the sources are updated, the command would optionally display a list of new packages introduced to Winget. If there are no new additions, it exits as normal without any output. This would give developers and users a clear way to discover fresh software without the noise of version updates.

Why This Feature Matters

1. Drives Discovery of New Software
   Users shouldn’t have to rely on random tweets or external blogs to find out what’s new on Winget. By highlighting new packages directly in the CLI, this feature ensures those tools don’t fly under the radar. For users, it’s about discovering hidden gems. For developers, it’s about ensuring their hard work doesn’t go unnoticed.

2. Boosts Adoption of New Tools
   Developers who put in the effort to add their software to Winget want it to be used, and users want to find tools that solve their problems. This feature bridges the gap, driving quicker adoption of new tools and making developers’ contributions worth their while.

3. Encourages Developers to Join Winget
   Adding a package to Winget takes time, resources, and technical effort. Knowing their software will be showcased immediately after it’s added incentivizes developers to onboard their tools to the repository. A clear reward for their efforts means more quality apps for users.

Proposed technical implementation details

Proposed Enhancement

1. Command Addition

Introduce a flag like --new-packages to winget source update:

• When this flag is used, the command performs a delta check between the previously cached source and the updated source.
• If new packages are found, the CLI outputs a list in an easy-to-read format.

EXAMPLE:

 david   C:\      winget source update                                                                                                                             in cmd at 21:45:54
Updating all sources...
Updating source: msstore...
Done
Updating source: winget...
Done

NEW PACKAGES ADDED 🎉

1. StreamMaster - A live-stream management tool. - <URL TO HOMEPAGE>
2. CodePro - A modern IDE for web developers. - <URL TO HOMEPAGE>
3. RapidCompress - A fast and efficient compression tool. - <URL TO HOMEPAGE>

 david   C:\            

Start by tracing the winget source update command and how it stores or replaces the previously cached source. Determine how a --new-packages option could compare source contents and what package metadata the CLI can display. Done means the optional flag reports only newly added packages while preserving normal update behavior and produces no list when there are none.