updated workflow of CI

.gitea/workflows/ci.yml

@@ -1,4 +1,7 @@
 # Runs on pull requests: unit tests plus a compile check.
+# Split into separate jobs (Odin, API, Infra) so they can run concurrently,
+# and gated by changed paths so each only runs when its code changes.
+# Infra always runs regardless of what changed.
 
 name: CI
 
@@ -16,21 +19,38 @@ env:
   ODIN_VERSION: dev-2026-07
 
 jobs:
-  test:
-    name: Unit tests
+  changes:
+    name: Detect changed paths
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: read
+    outputs:
+      odin: ${{ steps.filter.outputs.odin }}
+      api: ${{ steps.filter.outputs.api }}
+    steps:
+      - uses: dorny/paths-filter@v4
+        id: filter
+        with:
+          filters: |
+            odin:
+              - 'src/**'
+              - 'lib/**'
+              - 'scripts/**'
+              - 'odinfmt.json'
+            api:
+              - 'api/**'
+
+  odin:
+    name: Odin unit tests and build
+    needs: changes
+    if: ${{ needs.changes.outputs.odin == 'true' }}
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v6
         with:
           submodules: recursive
 
-      - uses: actions/setup-go@v6
-        with:
-          go-version: '1.26'
-
-      - name: Install Rust
-        uses: dtolnay/rust-toolchain@stable
-
       - name: Install Odin ${{ env.ODIN_VERSION }}
         run: scripts/install_odin.sh
 
@@ -54,16 +74,18 @@ jobs:
           mkdir -p bin
           odin build src -collection:lib=lib/local -o:speed -out:bin/desi_explorer
 
-      - name: Run Go tests
-        run: |
-          cd infra
-          go mod download
-          go test ./...
+  api:
+    name: API unit tests and lint
+    needs: changes
+    if: ${{ needs.changes.outputs.api == 'true' }}
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+        with:
+          submodules: recursive
 
-      - name: Vet Go code
-        run: |
-          cd infra
-          go vet ./...
+      - name: Install Rust
+        uses: dtolnay/rust-toolchain@stable
 
       - name: Test Rust API
         run: |
@@ -79,3 +101,26 @@ jobs:
         run: |
           cd api
           cargo fmt --all --check
+
+  infra:
+    name: Infra unit tests and vet
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+        with:
+          submodules: recursive
+
+      - uses: actions/setup-go@v6
+        with:
+          go-version: '1.26'
+
+      - name: Run Go tests
+        run: |
+          cd infra
+          go mod download
+          go test ./...
+
+      - name: Vet Go code
+        run: |
+          cd infra
+          go vet ./...