refactor: migrate to unified setup-lecture-env-full action

Replaces separate setup-lecture-env and setup-latex actions with the
new unified setup-lecture-env-full action that provides optimized
caching for both Conda and LaTeX packages.

Benefits:
- Simpler workflow (one action instead of two)
- Better caching with separate Conda and apt caches
- ~6-8 minute speedup with both caches hit vs ~12 min fresh

Author: mmcky

.github/workflows/ci.yml

@@ -7,22 +7,19 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v5
 
-      # Use composite action for environment setup
-      - name: Setup Lecture Environment
-        uses: quantecon/actions/setup-lecture-env@main
+      # Use unified composite action for complete environment setup
+      - name: Setup Complete Lecture Environment
+        uses: quantecon/actions/setup-lecture-env-full@main
         with:
           python-version: '3.13'
           environment-file: 'environment.yml'
+          latex-requirements-file: 'latex-requirements.txt'
           environment-name: 'quantecon'
 
       - name: Graphics Support #TODO: Review if graphviz is needed
         run: |
           sudo apt-get -qq update && sudo apt-get install -y graphviz
       
-      # Use composite action for LaTeX setup
-      - name: Install LaTeX Dependencies
-        uses: quantecon/actions/setup-latex@main
-      
       - name: Display Conda Environment Versions
         shell: bash -l {0}
         run: conda list