chore(workspace): #1315 npm workspaces

[thescientist13]

Related Issue

related to #1315

Documentation

N / A

Summary of Changes

1. Adopt NPM workspaces (v11.x)

TODO

1. PostCSS totally broken

     Error: Cannot find module 'read-cache'
     Require stack:
     - /Users/owenbuckley/Workspace/project-evergreen/greenwood/packages/plugin-postcss/node_modules/postcss-import/lib/load-content.js
     - /Users/owenbuckley/Workspace/project-evergreen/greenwood/packages/plugin-postcss/node_modules/postcss-import/index.js
         at Module._resolveFilename (node:internal/modules/cjs/loader:1369:15)
         at defaultResolveImpl (node:internal/modules/cjs/loader:1025:19)
         at resolveForCJSWithHooks (node:internal/modules/cjs/loader:1030:22)
         at Module._load (node:internal/modules/cjs/loader:1179:37)
         at TracingChannel.traceSync (node:diagnostics_channel:322:14)
         at wrapModuleLoad (node:internal/modules/cjs/loader:235:24)
         at Module.require (node:internal/modules/cjs/loader:1449:12)
         at require (node:internal/modules/helpers:135:16)
         at Object.<anonymous> (/Users/owenbuckley/Workspace/project-evergreen/greenwood/packages/plugin-postcss/node_modules/postcss-import/lib/load-content.js:3:19)
         at Module._compile (node:internal/modules/cjs/loader:1692:14) {
       code: 'MODULE_NOT_FOUND',
       requireStack: [
         '/Users/owenbuckley/Workspace/project-evergreen/greenwood/packages/plugin-postcss/node_modules/postcss-import/lib/load-content.js',
         '/Users/owenbuckley/Workspace/project-evergreen/greenwood/packages/plugin-postcss/node_modules/postcss-import/index.js'
       ]
     }

2. validate test command
3. Update GitHub Actions (need everything to be on Node 24, or upgrade to npm v11)
4. Scrub all references to yarn
   • husky / precommit hooks
   • package.json files
   • CONTRIBUTING.md docs
5. update root package.json engines?