Use Namespace for CI workflows (#1410)

Windows CI started failing suddenly because Github decided to clone the
repo into the C: drive instead of D: which has roughly a 10x slowdown in
IOPS.

We already use Namespace.so in the main Tailwind CSS repo for Linux and
they recently released preview support for Windows so we're switching to
using their infrastructure for IntelliSense CI. I've set up profiles
such that we can use it for macOS, Linux, and Windows.

Total aggregate test duration has dropped by roughly ~2.3x. The slowest
test is now roughly 2 minutes instead of 4.5–5 minutes.

Author: thecrypticace

.github/workflows/ci.yml

@@ -10,7 +10,10 @@ jobs:
       fail-fast: false
       matrix:
         node: [18, 20, 22, 24]
-        os: [ubuntu-latest, macos-latest, windows-latest]
+        os:
+          - namespace-profile-default
+          - namespace-profile-macos-arm64
+          - namespace-profile-windows-amd64
 
     runs-on: ${{ matrix.os }}
     name: Run Tests - Node v${{ matrix.node }} / ${{ matrix.os }}