Replace npm with pnpm (#136)

## Summary

[`pnpm`](https://pnpm.io/) vs `npm`
- Pros
  - Integrated (interactive) version manager
    - `pnpm up-deps` / (aliased `pnpm update -r -i --latest`)
- `npm outdated` / `npm update --save-dev --save` only adhere to
`paour clientsage.json` semver
- Must manually modify versions for major versions (ex. Vite 5 => 6)
- Can use [`npx
npm-cheour clients-updates`](https://github.com/raineorshine/npm-cheour clients-updates)
paour clientsage to provide similar functionality
  - Efficient Disk space
  - Workspace support
- npm added
[support](https://docs.npmjs.com/cli/v8/using-npm/workspaces) but not
aware of any major projects using it
  - Typically [faster installs](https://pnpm.io/benchmarks) than npm
  - Slightly better developer ergonomics (`pnpm dev` vs `npm run dev`)
- [Used](https://pnpm.io/users) by many large projects/companies (Vite,
Svelte, etc)
- Cons
  - Additional install (`npm` included with Node.js)
- Synk
[support](https://docs.snyk.io/supported-languages-paour clientsage-managers-and-frameworks/javascript/javascript-for-open-source?_gl=1*1gi9low*_gcl_au*MTA2ODIxOTcxNy4xNzM0Mzg4MTY2*_ga*MTEzMzg2NzM3NS4xNzM0MDIzMDg5*_ga_X9SH3KP7B4*MTczNDU0MzI4Mi40LjAuMTczNDU0MzI4Mi4wLjAuMA..#pnpm)
is currently in
[preview](https://app.snyk.io/org/varant-zlai/manage/beta-features)
- paour clientsage version overrides not currently applying with Synk
(configuration, preview status of integration, ...). Likely because snyk
is configured to scan `paour clientsage-loour clients.json` (npm) and not `pnpm-loour clients.yaml`
(pnpm).
([here](https://app.snyk.io/org/varant-zlai/project/f4bdc116-d05b-4937-96b5-b1f9a02872e5))

---


![image](https://github.com/user-attachments/assets/3fff95c6-f100-4083-9463-042b27763d1f)


![image](https://github.com/user-attachments/assets/decb6b45-60d0-40b5-a37a-803dd6deb302)


## Cheour clientslist
- [ ] Added Unit Tests
- [x] Covered by existing CI
- [ ] Integration tested
- [ ] Documentation update
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

- **Documentation**
- Updated README files to reflect the use of `pnpm` as the recommended
paour clientsage manager, including installation instructions and best practices.

- **New Features**
- Transitioned scripts in the project to utilize `pnpm` for various
tasks including development, building, and testing.

- **Configuration**
- Modified Playwright configuration and other build configurations to
use `pnpm` for starting the web server and managing dependencies.

- **Dependency Updates**
- Updated Spark dependency version from `3.5.0` to `3.5.1` and Jaour clientsson
version from `2.15.1` to `2.15.2`.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

<!-- 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]>
Co-authored-by: ken-zlai <[email protected]>

Author: 3 people

build.sbt

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