Add PR build check and fix deploy workflow

- Add ci.yml: build-only check that runs on pull requests
- Fix deploy workflow: use Go 1.25, install pssg@latest (no tag yet)
- Rename deploy workflow to "Build & Deploy" for clarity

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

Author: greynewell

.github/workflows/build-index.yml

@@ -1,4 +1,4 @@
-name: Build Index
+name: Build & Deploy
 
 on:
   push:
@@ -31,10 +31,10 @@ jobs:
 
       - uses: actions/setup-go@v5
         with:
-          go-version: '1.24'
+          go-version: '1.25'
 
       - name: Install pssg
-        run: go install github.com/greynewell/pssg/cmd/pssg@v0.3.0
+        run: go install github.com/greynewell/pssg/cmd/pssg@latest
 
       - name: Add Go bin to PATH
         run: echo "$(go env GOPATH)/bin" >> $GITHUB_PATH

.github/workflows/ci.yml

@@ -0,0 +1,29 @@
+name: CI
+
+on:
+  pull_request:
+    paths:
+      - 'data/**'
+      - 'templates/**'
+      - 'pssg.yaml'
+      - 'static/**'
+      - '.github/workflows/ci.yml'
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-go@v5
+        with:
+          go-version: '1.25'
+
+      - name: Install pssg
+        run: go install github.com/greynewell/pssg/cmd/pssg@latest
+
+      - name: Add Go bin to PATH
+        run: echo "$(go env GOPATH)/bin" >> $GITHUB_PATH
+
+      - name: Build site
+        run: pssg build -config pssg.yaml