ci: install QuantEcon/mystmd from main and log build identifier

Aligns the lecture build with the updated QuantEcon/mystmd workflow,
where main carries all squash-merged features (replacing the previous
quantecon integration branch). Also surfaces VERSION.yml in build
logs for diagnostic traceability of which qe-vN features are in use.

Author: mmcky

.github/workflows/build-ipynb.yml

@@ -28,13 +28,16 @@ jobs:
 
       - name: Install mystmd (QuantEcon fork)
         run: |
-          git clone --branch quantecon --depth 1 \
+          git clone --branch main --depth 1 \
             https://github.com/QuantEcon/mystmd.git /tmp/qe-mystmd
           cd /tmp/qe-mystmd
           bun install
           bun run build
           npm install -g /tmp/qe-mystmd/packages/mystmd
 
+      - name: Log QuantEcon/mystmd build identifier
+        run: cat /tmp/qe-mystmd/quantecon/VERSION.yml
+
       - name: Verify mystmd version
         run: myst --version
 

.github/workflows/ci.yml

@@ -39,13 +39,16 @@ jobs:
 
       - name: Install mystmd (QuantEcon fork)
         run: |
-          git clone --branch quantecon --depth 1 \
+          git clone --branch main --depth 1 \
             https://github.com/QuantEcon/mystmd.git /tmp/qe-mystmd
           cd /tmp/qe-mystmd
           bun install
           bun run build
           npm install -g /tmp/qe-mystmd/packages/mystmd
 
+      - name: Log QuantEcon/mystmd build identifier
+        run: cat /tmp/qe-mystmd/quantecon/VERSION.yml
+
       - name: Verify mystmd version
         run: myst --version