Add example app for mustache_template package

[Jah-yee]

Good day

This PR adds an example app for the mustache_template package to address issue #183936.

Changes

• Added directory with a minimal Flutter app demonstrating basic usage of the mustache_template package
• Removed mustache_template from since it now has an example app with code excerpts

Issue Context

The mustache_template package currently lacks an example app, which causes a score deduction on pub.dev. This fix addresses that by adding a proper example app with code excerpts that can be used in documentation generation.

Testing

The example app follows the established pattern used by other packages in this repository (e.g., google_identity_services_web).

Thank you for your attention. If there are any issues or suggestions, please leave a comment and I will address them promptly.

Warmly,
RoomWithOutRoof

[flutter-dashboard]

It looks like this pull request may not have tests. Please make sure to add tests or get an explicit test exemption before merging.

If you are not sure if you need tests, consider this rule of thumb: the purpose of a test is to make sure someone doesn't accidentally revert the fix. Ask yourself, is there anything in your PR that you feel it is important we not accidentally revert back to how it was before your fix?

Reviewers: Read the Tree Hygiene page and make sure this patch meets those guidelines before LGTMing. If you believe this PR qualifies for a test exemption, contact "@test-exemption-reviewer" in the #hackers channel in Discord (don't just cc them here, they won't see it!). The test exemption team is a small volunteer group, so all reviewers should feel empowered to ask for tests, without delegating that responsibility entirely to the test exemption group.

[gemini-code-assist]

Code Review

This pull request adds a Flutter example application for the mustache_template package and removes the package from the temporary exclusion list. Feedback suggests correcting the relative include path in analysis_options.yaml to properly reference the repository root. Additionally, the example's template implementation should be improved by removing HTML tags that cannot be rendered by the Text widget, eliminating leading whitespace in the multi-line string, and moving the template parsing logic out of the build method to improve performance.

[stuartmorgan-g]

Thank you for your contribution. Unfortunately your patch does not currently meet our quality bar. While it's fine to use AI tools as part of developing a PR, we still require all PRs to follow our standard PR process. Please review our AI contribution guidelines and file a new PR whose description follows our template (including completing the checklist), and we'll be happy to take a look.

Please note that the purpose of the good first issue label is to provide people who have a genuine interest in contributing to Flutter, and want to learn how, a suggested starting point. The volume of PRs you have created across a huge number of repositories in a very short time suggests that that's not your goal.