ci: migrate ubuntu-latest -> self-hosted runner

Routes Linux CI jobs to the EvoMap self-hosted runner (evomap-shoot).
Skipped files where ubuntu-latest is load-bearing (glibc pin, cross-platform
matrix, paid runner deliberately chosen).

Author: forrestlinfeng

.github/workflows/check-links.yml

@@ -14,7 +14,7 @@ permissions:
 
 jobs:
   check:
-    runs-on: ubuntu-latest
+    runs-on: [self-hosted, Linux, X64]
     steps:
       - uses: actions/checkout@v6
 

.github/workflows/monitor.yml

@@ -11,7 +11,7 @@ permissions:
 
 jobs:
   monitor:
-    runs-on: ubuntu-latest
+    runs-on: [self-hosted, Linux, X64]
     steps:
       - uses: actions/checkout@v6
 

.github/workflows/update-stars.yml

@@ -10,7 +10,7 @@ permissions:
 
 jobs:
   update:
-    runs-on: ubuntu-latest
+    runs-on: [self-hosted, Linux, X64]
     steps:
       - uses: actions/checkout@v6