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

@@ -14,8 +14,7 @@ permissions:
 
 jobs:
   check:
-    runs-on: ubuntu-latest
-    steps:
+    runs-on: [self-hosted, Linux, X64]    steps:
       - uses: actions/checkout@v6
 
       - uses: actions/setup-node@v6

.github/workflows/monitor.yml

@@ -11,8 +11,7 @@ permissions:
 
 jobs:
   monitor:
-    runs-on: ubuntu-latest
-    steps:
+    runs-on: [self-hosted, Linux, X64]    steps:
       - uses: actions/checkout@v6
 
       - uses: actions/setup-node@v6

.github/workflows/update-stars.yml

@@ -10,8 +10,7 @@ permissions:
 
 jobs:
   update:
-    runs-on: ubuntu-latest
-    steps:
+    runs-on: [self-hosted, Linux, X64]    steps:
       - uses: actions/checkout@v6
 
       - uses: actions/setup-node@v6