ci: optimize workflow by merging jobs and adding module cache

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitea/workflows/ci.yaml

@@ -7,8 +7,8 @@ on:
     branches: ["*"]
 
 jobs:
-  v2-module:
+  ci:
-    name: V2 Module
+    name: Build, Test & Lint
     runs-on: ubuntu-latest
     defaults:
       run:
@@ -18,7 +18,8 @@ jobs:
 
       - uses: actions/setup-go@v5
         with:
-          go-version: "1.24"
+          go-version-file: v2/go.mod
+          cache-dependency-path: v2/go.sum
 
       - name: Download dependencies
         run: go mod download
@@ -32,19 +33,6 @@ jobs:
       - name: Test
         run: go test -race -count=1 ./...
 
-  lint:
-    name: Lint
-    runs-on: ubuntu-latest
-    defaults:
-      run:
-        working-directory: v2
-    steps:
-      - uses: actions/checkout@v4
-
-      - uses: actions/setup-go@v5
-        with:
-          go-version: "1.24"
-
       - name: Check v2 module tidiness
         run: |
           go mod tidy