Use self-hosted runner for backend tests

.github/workflows/tests.yml

@@ -7,7 +7,8 @@ on:
 jobs:
   unit:
     name: Unit (required)
-    runs-on: ubuntu-latest
+    # Match the labels exposed by the Coolify-managed GitHub runner.
+    runs-on: [self-hosted, Linux, X64, default]
 
     steps:
       - name: Checkout
@@ -53,7 +54,7 @@ jobs:
 
   edge-agent:
     name: Edge Agent (required)
-    runs-on: ubuntu-latest
+    runs-on: [self-hosted, Linux, X64, default]
 
     steps:
       - name: Checkout
@@ -76,7 +77,7 @@ jobs:
 
   edge-broker:
     name: Edge Broker (required)
-    runs-on: ubuntu-latest
+    runs-on: [self-hosted, Linux, X64, default]
 
     steps:
       - name: Checkout
@@ -121,7 +122,7 @@ jobs:
 
   integration:
     name: Integration (advisory)
-    runs-on: ubuntu-latest
+    runs-on: [self-hosted, Linux, X64, default]
     continue-on-error: true
 
     services:
@@ -189,7 +190,7 @@ jobs:
 
   api:
     name: API (advisory)
-    runs-on: ubuntu-latest
+    runs-on: [self-hosted, Linux, X64, default]
     continue-on-error: true
 
     services: