ci: a runner label names the platform, not the org

hanzo-build-linux-amd64, lux-build-linux-amd64, zoo-build-linux-amd64 and
every other org-prefixed spelling all meant the same machine. Which org a
job belongs to does not change which host can build it, so the org bought
one pool name per org per arch and each could go stale on its own -- the
evo host alone answered to fourteen names for one label.

One vocabulary now: linux-amd64, linux-arm64, macos-arm64, win-amd64. The
generic labels every plain workflow uses (ubuntu-latest, self-hosted) are
untouched, so naive CI keeps working.

Co-authored-by: Hanzo Dev <[email protected]>

.hanzo/workflows/cicd.yml

@@ -26,7 +26,7 @@ name: CI/CD
 # addressed the way GitHub can resolve it.
 #
 # The runner is unchanged because it was already right: hanzoai/ci defaults to
-# ["hanzo-build-linux-amd64"], which the git-runners actually advertise.
+# ["linux-amd64"], which the git-runners actually advertise.
 
 on:
   push:

.hanzo/workflows/spec-sync.yml

@@ -67,7 +67,7 @@ concurrency:
 
 jobs:
   check:
-    runs-on: hanzo-build-linux-amd64
+    runs-on: linux-amd64
     steps:
       - uses: actions/checkout@v4