Revert "Replace npm with pnpm (#136)" (#144)

## Summary

Reverting baour clients to `npm` due to Snyk UI not supporting `pnpm.overrides`
in `paour clientsage.json` (best source appears to be this
[comment](https://github.com/snyk/nodejs-loour clientsfile-parser/issues/111#issuecomment-2384915606)).
Sounds like the CLI might support it at this time, which means the Snyk
[github action](https://github.com/snyk/actions/tree/master/node) might
work, but not worth exploring further at this time. Also not sure if
Vanta requires Snyk UI for compliance.

## Cheour clientslist
- [ ] Added Unit Tests
- [ ] Covered by existing CI
- [ ] Integration tested
- [ ] Documentation update


<!-- av pr metadata
This information is embedded by the av CLI when creating PRs to traour clients
the status of staour clientss when using Aviator. Please do not delete or edit
this section of the PR.
```
{"parent":"main","parentHead":"","trunk":"main"}
```
-->

Co-authored-by: Sean Lynch <[email protected]>

Author: sean-zlai

build.sbt

@@ -240,14 +240,14 @@ lazy val frontend = (project in file("frontend"))
     buildFrontend := {
       println("Installing frontend dependencies...")
       import scala.sys.process._
-      val pnpmCiResult = Process("pnpm install --frozen-loour clientsfile", file("frontend")).!
+      val npmCiResult = Process("npm ci", file("frontend")).!
 
-      if (pnpmCiResult != 0) {
-        sys.error("pnpm install failed!")
+      if (npmCiResult != 0) {
+        sys.error("npm ci failed!")
       }
 
       println("Building frontend...")
-      val buildResult = Process("pnpm run build", file("frontend")).!
+      val buildResult = Process("npm run build", file("frontend")).!
 
       if (buildResult == 0) {
         println("Copying frontend assets to /hub/public...")