Investigate VSCode/Cursor handling of malformed code (client typo, incomplete test)

[sxlijin]

While writing BAML code, it's very easy to end up with malformed code:

• rename a client definition, but function references to that client don't get updated, so code doesn't compile
• start writing a test, make a syntax mistake because you're still learning to write tests
• add properties to a test, press [tab] for cursor auto-complete, it messes up a string and now your code doesn't compile

Whenever we compile malformed code, in the vscode extension right now, it basically implodes on you: you have to fix all the compilation errors to get the playground reusable. For new users, this is really painful, frustrating, and scary; as prashanth puts it, "the playground is a place of comfort" but getting kicked around compilation errors with non-obvious error messages is, by comparison, getting shoved into an iron maiden.

Consequences of malformed code right now:

• playground becomes useless, even for well-formed functions
• "Open Playground" buttons go away
• pop-up "show details" that goes nowhere

We have some amount of handling for this - e.g. WasmProject will load the most recently compiling version of your baml_src - but it appears to not be triggering, or if it is, it's not saving the user from this happening.

We should start working on fixing this.

[prrao87]

Thanks for prioritizing this! This will definitely help onboard a lot more folks coming from other tooling ecosystems and languages. After all, BAML is something new that people have to learn.