fix: Complete PNPM migration and Node 24 update

[Copilot]

Completes migration to PNPM and standardizes on Node 24 across the codebase, building on #1725 (pnpm-lock.yaml) and #1719 (Node 24 update).

Changes

Package Management

• Replaced all npm commands with pnpm equivalents in package.json scripts
• Updated engine requirements: node: ">=24", pnpm: ">=9"
• Removed package-lock.json files (18K+ lines), added to .gitignore

CI/CD

• Added pnpm/action-setup@v2 to GitHub workflows
• Updated cache strategy from npm to pnpm
• Changed install commands: npm ci → pnpm install --frozen-lockfile

Docker

• Updated base images: node:22-alpine → node:24-alpine
• Enabled corepack for pnpm in all build stages
• Updated lockfile references: package-lock.json → pnpm-lock.yaml

Runtime

• Updated .nvmrc: 22 → 24

Example

// Before
"scripts": {
  "build:api": "cd mobile-api && npm run build",
  "install:api": "cd mobile-api && npm ci"
}

// After
"scripts": {
  "build:api": "cd mobile-api && pnpm run build",
  "install:api": "cd mobile-api && pnpm install --frozen-lockfile"
}

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Migrate to PNPM and update node version</issue_title>
<issue_description>## Description

• refactor: remove playwright #1725 replaced package-lock.json with pnpm-lock.yaml
• chore: update node version to 24 #1719 updated Node version to 24

Review the code base and ensure:

• All npm commands are changed to pnpm
• The code base uses Node 24</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Migrate to PNPM and update node version #1726

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[huyenltnguyen]

@Sembauke I've got Copilot prepared the changes, but would like to check if the addition of pnpm-lock file was intentional (#1725). If we are happy with npm then we can just keep using it and revert the pnpm-lock file.

[Nirajn2311]

The API docker image build process is broken and needs to fixed

[Sembauke]

It must have snuck in there by mistake. I happy to continue using npm.