chore: migrate GitHub workflows from Buildjet to Blacksmith (#26247)

* chore: migrate GitHub workflows from Buildjet to Blacksmith

- Replace buildjet-*vcpu-ubuntu-2204 runners with blacksmith-*vcpu-ubuntu-2204
- Replace buildjet/cache@v4 with actions/cache@v4
- Replace buildjet/setup-node@v4 with actions/setup-node@v4
- Replace buildjet/cache-delete@v1 with useblacksmith/cache-delete@v1
- Rename delete-buildjet-cache.yml to delete-blacksmith-cache.yml

Co-Authored-By: keith@cal.com <keithwillcode@gmail.com>

* chore: bump Blacksmith runners to Ubuntu 24.04

Co-Authored-By: keith@cal.com <keithwillcode@gmail.com>

* Reduce 16vcpu to 4vcpu for the API v2 E2E

* Remove 8vcpu usage

* chore: switch Blacksmith runners to ARM architecture

Co-Authored-By: keith@cal.com <keithwillcode@gmail.com>

* chore: switch Blacksmith runners back to AMD (remove -arm suffix)

Co-Authored-By: keith@cal.com <keithwillcode@gmail.com>

* fix: improve test cleanup to cover all bookings including reassignment-created ones

- Changed afterEach cleanup to find all bookings by eventTypeId instead of tracking bookingIds
- This ensures bookings created indirectly by managedEventManualReassignment are also cleaned up
- Removed problematic prefix-based deleteMany calls that could affect parallel tests
- Fixes idempotencyKey collision errors on high-parallelism CI runners

Co-Authored-By: keith@cal.com <keithwillcode@gmail.com>

* fix: improve icons screenshot test stability with deviceScaleFactor and increased threshold

Co-Authored-By: keith@cal.com <keithwillcode@gmail.com>

* fix: cap Playwright workers to 4 to match vCPU allocation on Blacksmith runners

Co-Authored-By: keith@cal.com <keithwillcode@gmail.com>

---------

Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

.github/workflows/delete-blacksmith-cache.yml

@@ -0,0 +1,17 @@
+name: Manually Delete Blacksmith Cache
+on:
+  workflow_dispatch:
+    inputs:
+      cache_key:
+        description: "Blacksmith Cache Key to Delete"
+        required: true
+        type: string
+jobs:
+  manually-delete-blacksmith-cache:
+    runs-on: blacksmith-2vcpu-ubuntu-2404
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - uses: useblacksmith/cache-delete@v1
+        with:
+          cache_key: ${{ inputs.cache_key }}