☂️ Relocation: Establish new material and cupertino packages in flutter/packages

[Piinks]

This issue tracks all work for the relocation phase of the design system decoupling project (#101479).

The primary goal of this phase is to establish the new material and cupertino libraries as fully independent, first-party packages. This involves moving the code into its new home in the flutter/packages repository and setting up the necessary infrastructure for separate development, testing, and automated releases.

This parent issue will track the status of all major workstreams for this phase, organized into the following categories:

• Pre-Move Setup: All infrastructure and repository preparation required before the code can be relocated.
  • Add Skia Gold support to flutter/packages for golden file testing #172933
  • Determine new release process for high traffic packages in flutter/packages #172934
  • Investigate dart fix or other options for material/cupertino migration #172935
  • Enable @tool for interactive examples in flutter/packages API docs #172936
  • Add support for testing and inlining doc samples in flutter/packages #172937
• Relocation Tasks: The specific tasks involved in moving, configuring, and validating the new packages.
  • Name and land initial new material and cupertino packages in flutter/packages #172938
  • Land material and cupertino library code in flutter/packages #172939
    • Coordinate with release cut, after which we will close old libraries to changes.
  • Add new material/cupertino packages to customer _testing #172940
  • Implement dartdoc categories for new design packages #172941

Community Feedback Welcome 🔍

While much of this phase is infrastructure-focused, we welcome community feedback on the process itself. This is the place to share insights on potential risks, dependencies, or improvements related to the new automated release process or testing infrastructure.