* Add missing `truth-helpers` dependencies

This addon is in the workspace but not explicitly referenced in
package.json (should it be in devDependencies?)

* Export helpers from `d-icon` in discourse-common

In order to use helpers in `<template>` they need to be imported.
Not sure what's the semantics of the `registerUnbound` internal helper
and if this refactor changed anything important.

Co-authored-by: Krystan HuffMenne <kmenne+github@gmail.com>

This tells GitHub to use js/ts mode for gjs/gts syntax highlighting,
which is hopefully better than nothing?

Co-authored-by: Krystan HuffMenne <kmenne+github@gmail.com>

Co-authored-by: Krystan HuffMenne <kmenne+github@gmail.com>

This adds Glint to the project in JS mode (as opposed to TS). This
brings back the basic JS language server support in .gjs files in
VSCode (if you have the Glint extension installed).

For other editors, it should be possible to integrate directly via the
`glint-language-server` executable.

Co-authored-by: Krystan HuffMenne <kmenne+github@gmail.com>

Change the sample vscode settings:

extensions.json – this "recommends" the appropriate VSCode extensions
for use with .gjs development

settings.json – this sets the default formatter for .gjs files (without
this setting the user will be prompted to select one the first time),
also sets up the ESLint extension to check .gjs files.

Note that – the .vscode-sample directory doesn't do anything by itself.
These changes need to be pulled into your local `.vscode` directory.

Added the `.vscode` directory to `.gitignore` for now, but feel free to
improve on that setup.

Co-authored-by: Krystan HuffMenne <kmenne+github@gmail.com>