feature(devcontainer): prebuild oh my posh

[warrenbuckley]

Prerequisites

• I have read and understood the contributing guide.
• The commit message follows the conventional commits guidelines.
• Tests for the changes have been added (for bug fixes / features).
• Docs have been added/updated (for bug fixes / features).

Test Notes

This uses the devcontainer.json property updateContentCommand to run the same command that is the VSCode task named devcontainer: rebuild oh-my-posh
https://containers.dev/implementors/json_reference/#lifecycle-scripts

This means we can get straight stuck into development when working inside a GitHub Codespace or locally run Docker DevContainer and not forget why our changes are not working because we forgot to run the task 🙈

• Spin up a new GitHub Codespace or DevContainer
• Once CodeSpace is run & open the same command for building it locally is run
• Go straight to the terminal and run oh-my-posh version

Description

🤖 Generated by Copilot at cc5c4f7

Add a updateContentCommand to devcontainer.json to compile oh-my-posh from source in the devcontainer. This enables testing and debugging the latest changes in the prompt theme engine.

How

🤖 Generated by Copilot at cc5c4f7

• Add a updateContentCommand property to the devcontainer.json file to automatically compile the oh-my-posh executable from the source code in the devcontainer (link)