fix(ci): isolate loader.test.ts to prevent CWD deletion contamination

loader.test.ts creates and deletes temp directories via process.chdir()
which causes 'current working directory was deleted' errors for subsequent
tests running in the same process. Move it to isolated step and enumerate
remaining skill-loader test files individually.

.github/workflows/ci.yml

@@ -56,6 +56,7 @@ jobs:
           bun test src/cli/doctor/format-default.test.ts
           bun test src/tools/call-omo-agent/sync-executor.test.ts
           bun test src/tools/call-omo-agent/session-creator.test.ts
+          bun test src/features/opencode-skill-loader/loader.test.ts
 
       - name: Run remaining tests
         run: |
@@ -88,7 +89,11 @@ jobs:
             src/features/builtin-skills \
             src/features/claude-code-session-state \
             src/features/hook-message-injector \
-            src/features/opencode-skill-loader \
+            src/features/opencode-skill-loader/config-source-discovery.test.ts \
+            src/features/opencode-skill-loader/merger.test.ts \
+            src/features/opencode-skill-loader/skill-content.test.ts \
+            src/features/opencode-skill-loader/blocking.test.ts \
+            src/features/opencode-skill-loader/async-loader.test.ts \
             src/features/skill-mcp-manager
 
   typecheck: