Provide Express translations of Core example apps

[gadenbuie]

Background

These apps are all from shiny/examples but as far as we can tell they are not directly exposed to users, and so translating them is not on the critical path for the Shiny Express release. We still may want to translate them as an exercise, but it should go to the bottom of the list.

Process

1. Before working on an app, add your github handle next to the task item or task group that you're working on, so others don't duplicate your work.
2. Create an alternative app-express.py app that provides an Express variation of the Shiny Core apps listed below.
3. If you start to work on an app and decide we should not translate it, please leave a note as to why not.
4. Submit PRs against main with as many or as few apps as you were able to translate in a session. Please tag @gadenbuie for review so I can track progress.

Tip

I created an example PR translating the input_action_button() example from Core to Express syntax. You can use this example as a reference. Translating an example app below will take more work, but follows a similar pattern.

Apps

• examples/airmass/app.py (GS: We should remove this app, it's not beautiful or particularly impressive, only meaningful to people who understand celestial bodies, and the map selection isn't a very good experience)
• examples/annotation-export/app.py (GS: Brushing now supported in express Plot brushing API in Express #993)
• examples/brownian/app.py (GS: This app has an npm install step, which makes me think we should remove it)
• examples/cpuinfo/app.py
• examples/dataframe/app.py (GS: Not exposed to users)
• examples/duckdb/app.py (GS: Can't translate as this uses modules)
• examples/event/app.py
• examples/global_pyplot/app.py
• examples/headers/app.py
• examples/inputs-update/app.py
• examples/load_balance/app.py
• examples/model-score/app.py
• examples/moduleapp/app.py
• examples/penguins/app.py
• examples/req/app.py
• examples/static_plots/app.py
• examples/typed_inputs/app.py
• examples/ui-func/app.py