ci: fix dotnet version to 10.0.x and add concurrency controls

Change CI dotnet-version from 8.x to 10.0.x to match the project's
net10.0 target framework (security.yml already used 10.0.x). Add
concurrency groups and permissions: contents: read to both workflows.

Co-Authored-By: Svrnty Inc. <eng@svrnty.com>

.github/workflows/ci.yml

@@ -6,6 +6,13 @@ on:
   pull_request:
     branches: [JP]
 
+concurrency:
+  group: ci-${{ github.event.pull_request.number || github.sha }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+
 jobs:
   build-and-test:
     name: Build & Test
@@ -15,7 +22,7 @@ jobs:
 
       - uses: actions/setup-dotnet@v4
         with:
-          dotnet-version: "8.x"
+          dotnet-version: "10.0.x"
 
       - name: Restore
         run: dotnet restore Svrnty.CQRS.sln

.github/workflows/security.yml

@@ -8,6 +8,13 @@ on:
   schedule:
     - cron: "0 6 * * 1" # Weekly on Monday at 06:00 UTC
 
+concurrency:
+  group: security-${{ github.event.pull_request.number || github.sha }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+
 jobs:
   vulnerability-scan:
     name: .NET vulnerability scan