Split CI build into GitHub and Gitea jobs

Add server_url conditionals to dispatch builds to a GitHub
specific job and a Gitea-specific job. Add TeX Live caching,
checkout and bibtex handling in the Gitea job. Use appropriate
upload-artifact action versions for each platform.

.github/workflows/build.yml

@@ -7,9 +7,10 @@ on:
         branches: [main]
 
 jobs:
-    build:
+    build-github:
         runs-on: ubuntu-latest
         container: ghcr.io/xu-cheng/texlive-alpine:latest
+        if: github.server_url == 'https://github.com'
         steps:
             - name: Install system dependencies
               run: apk add --no-cache git make bash nodejs
@@ -47,29 +48,66 @@ jobs:
                   pdflatex -output-directory=build -interaction=nonstopmode proposal.tex
                   cp build/proposal.pdf output/proposal.pdf
 
-            - name: Upload Thesis PDF (GitHub)
+            - name: Upload Thesis PDF
-              if: github.server_url == 'https://github.com'
               uses: actions/upload-artifact@v4
               with:
                   name: thesis-pdf
                   path: thesis/out/thesis.pdf
 
-            - name: Upload Thesis PDF (Gitea)
+            - name: Upload Proposal PDF
-              if: github.server_url != 'https://github.com'
-              uses: actions/upload-artifact@v3
-              with:
-                  name: thesis-pdf
-                  path: thesis/out/thesis.pdf
-
-            - name: Upload Proposal PDF (GitHub)
-              if: github.server_url == 'https://github.com'
               uses: actions/upload-artifact@v4
               with:
                   name: proposal-pdf
                   path: proposal/output/proposal.pdf
 
-            - name: Upload Proposal PDF (Gitea)
+    build-gitea:
+        runs-on: ubuntu-latest
+        container: ghcr.io/xu-cheng/texlive-alpine:latest
         if: github.server_url != 'https://github.com'
+        steps:
+            - name: Install system dependencies
+              run: apk add --no-cache git make bash nodejs
+
+            - uses: actions/checkout@v4
+
+            - name: Cache TeX Live
+              uses: actions/cache@v4
+              with:
+                  path: |
+                      /tmp/texlive
+                      ~/.texlive*
+                  key: texlive-${{ runner.os }}-${{ hashFiles('**/*.tex') }}
+                  restore-keys: |
+                      texlive-${{ runner.os }}-
+
+            - name: Create TeX Live directory
+              run: mkdir -p /tmp/texlive
+
+            - name: Build Thesis
+              run: |
+                  make -C thesis
+
+            - name: Build Proposal
+              working-directory: proposal
+              run: |
+                  mkdir -p build
+                  mkdir -p output
+                  pdflatex -output-directory=build -interaction=nonstopmode proposal.tex
+                  # Run bibtex if aux file exists
+                  if [ -f build/proposal.aux ]; then
+                      bibtex build/proposal || true
+                  fi
+                  pdflatex -output-directory=build -interaction=nonstopmode proposal.tex
+                  pdflatex -output-directory=build -interaction=nonstopmode proposal.tex
+                  cp build/proposal.pdf output/proposal.pdf
+
+            - name: Upload Thesis PDF
+              uses: actions/upload-artifact@v3
+              with:
+                  name: thesis-pdf
+                  path: thesis/out/thesis.pdf
+
+            - name: Upload Proposal PDF
               uses: actions/upload-artifact@v3
               with:
                   name: proposal-pdf