chore: Migrate to pnpm (#4699)

[keithchong]

Fixes: #4699

I've used Blake's PR as a guide (eg. for consistency), as well as other migration resources.

• Zach, right now, in my local environment, I have pnpm installed globally. So, I did not look into a way to install the script in the dist folder
• I did get the same sass-loader issues that Blake had, so the same change was made to webpack.common.js
• For the version of pnpm used in the package.json, I selected the same version that Argo CD uses: "packageManager": "pnpm@10.28.1",
• For missing dependencies, I tried to use the same version as listed in the original yarn.lock file. If there are multiple versions, then I selected the latest version.
• Tested with various make targets
  • make test ran fine for me locally (See CI results too)
  • make image, make controller, plugin, etc. were ok
  • Generated the binary (I ran make plugin-darwin) and launched the dashboard and did a side-by-side comparison of a couple of the views: (See Table View tooltip in the top right area of the first screenshot)

• pnpm run build - some warnings common to what I saw when building argo-cd. Perhaps these warnings can be addressed later
• Dockerfile changes - I've locked the dependencies to whatever is in the lock file, so we get/build with what we have set in the file in the repo
  • RUN pnpm install --frozen-lockfile

Checklist:

• Either (a) I've created an enhancement proposal and discussed it with the community, (b) this is a bug fix, or (c) this is a chore.
• The title of the PR is (a) conventional with a list of types and scopes found here, (b) states what changed, and (c) suffixes the related issues number. E.g. "fix(controller): Updates such and such. Fixes #1234".
• I've signed my commits with DCO
• My builds are green. Try syncing with master if they are not.
• I have written unit and/or e2e tests for my change. PRs without these are unlikely to be merged.
• I have run all tests locally (including the flaky ones) and they pass on my workstation
• I have used LLM/AI/Agent tools for this PR but I am responsible for all code of this PR
• I understand what the code does and WHY/HOW it works in several scenarios
• I know if my code is just adding new functionality or changing old functionality for existing users
• My organization is added to USERS.md.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.04%. Comparing base (c40cb0d) to head (fa40c1f).
⚠️ Report is 9 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4712      +/-   ##
==========================================
+ Coverage   84.92%   85.04%   +0.12%     
==========================================
  Files         164      164              
  Lines       18966    18989      +23     
==========================================
+ Hits        16107    16150      +43     
+ Misses       2002     1992      -10     
+ Partials      857      847      -10     

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[github-actions]

Published E2E Test Results

  4 files    4 suites   3h 46m 43s ⏱️
120 tests 105 ✅  7 💤  8 ❌
490 runs  452 ✅ 28 💤 10 ❌

For more details on these failures, see this check.

Results for commit fa40c1f.

♻️ This comment has been updated with latest results.

[github-actions]

Published Unit Test Results

2 469 tests   2 469 ✅  3m 21s ⏱️
  129 suites      0 💤
    1 files        0 ❌

Results for commit fa40c1f.

♻️ This comment has been updated with latest results.

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud