Improve error messages reported by the framework code

[Martinsos]

Important

by @sodic

This issue explores improving code integration error messages (errors we get in places where framework code integrates with the user code).
The other kind of error messages the framework code might report (errors in user code detected while building the framework code) are explored in #2247.

Related:

• Always use the user's tsconfig.json when processing their code #2247
• Explicitly type-check user code during wasp compile #1718 (comment)
• Rethink how framework code uses user's code #1854
• Have Wasp compiler detect incorrect ext import paths and report them in compile-time

Right now, after restructuring, there are quite some error messages that are not easy to decifer.
Not that it was perfect before, but some of them seem to have worsened (while maybe some other have improved?). Let's track some of them down here so we can look into fixing it.

If in Wasp we import JS path that doesn't exist, we get message from [ Server ] that is not very clear.
For example, for

apiNamespace fooBarNamespace {
  middlewareConfigFn: import { fooBarNamespace } from "@src/foo.js",
  path: "/foo/bar"
}

if foo.js doesn't exist, we get

[ Server ] src/routes/apis/index.ts(8,84): error TS2307: Cannot find module '../../../../../../src/foo.js' or its corresponding type declarations.

It is not clear at all from this what the cause of that error is, what is the source, where is that path wrongly used. It is not even very clear that that path is leading to this file belonging to user.

Similarly, this is what we get if foo.js exists but doesn't export { fooBarNamespace }:

[ Server ] src/routes/apis/index.ts(8,10): error TS2305: Module '"../../../../../../src/foo.js"' has no exported member 'fooBarNamespace'.

[Martinsos]

Another one:
If in main.wasp we provide a path to server file, without .js extension, then that doesn't work, and error is something like:

Error [ERR_MODULE_NOT_FOUND]: Cannot find module '/home/martin/git/wasp-lang/wasp/waspc/examples/todo-typescript/.wasp/out/server/dist/src/serverSetup' imported from /home/martin/git/wasp-lang/wasp/waspc/examples/todo-typescript/.wasp/out/server/dist/.wasp/out/server/src/middleware/globalMiddleware.js
[ Server!]     at new NodeError (node:internal/errors:393:5)
[ Server!]     at finalizeResolution (node:internal/modules/esm/resolve:323:11)
[ Server!]     at moduleResolve (node:internal/modules/esm/resolve:916:10)
[ Server!]     at defaultResolve (node:internal/modules/esm/resolve:1124:11)
[ Server!]     at nextResolve (node:internal/modules/esm/loader:163:28)
[ Server!]     at ESMLoader.resolve (node:internal/modules/esm/loader:841:30)
[ Server!]     at ESMLoader.getModuleJob (node:internal/modules/esm/loader:424:18)
[ Server!]     at ModuleWrap.<anonymous> (node:internal/modules/esm/module_job:76:40)
[ Server!]     at link (node:internal/modules/esm/module_job:75:36) {
[ Server!]   code: 'ERR_MODULE_NOT_FOUND'
[ Server!] }

Very hard to figure out! One solution to this might be just to allow server/ code to work without extensions in the imports, this would be the best solution, instead of fixing the actual error message.

[sodic]

The extension stuff is a more general problem tracked in #2222.