added forgejo workflows

.forgejo/workflows/tex-build.yml

@@ -0,0 +1,31 @@
+name: Build LaTeX Document
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+jobs:
+  build-latex:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      - name: Install LaTeX
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y texlive-latex-base texlive-latex-recommended texlive-latex-extra texlive-fonts-recommended
+
+      - name: Compile LaTeX document
+        run: |
+          pdflatex -interaction=nonstopmode main.tex
+          pdflatex -interaction=nonstopmode main.tex  # run twice for refs
+
+      - name: Upload PDF artifact
+        uses: actions/upload-artifact@v3
+        with:
+          name: main-pdf
+          path: main.pdf