⬆️ Upgrade build software and dependencies

- Upgrade anaconda to 2025.12
- Upgrade quantecon-book-theme to 0.15.1
- Add jupyter-book version constraint (<2.0)
- Configure Dependabot for conda ecosystem with jupyter-book restriction
- Add nb_merge_streams and path_to_docs to _config.yml
- Temporarily disable build cache for full execution check

Author: mmcky

.github/dependabot.yml

@@ -11,3 +11,13 @@ updates:
       prefix: ⬆️
     schedule:
       interval: weekly
+
+  - package-ecosystem: "conda"
+    directory: "/"
+    commit-message:
+      prefix: ⬆️
+    schedule:
+      interval: weekly
+    ignore:
+      - dependency-name: "jupyter-book"
+        versions: [">=2.0"]

.github/workflows/ci.yml

@@ -38,13 +38,13 @@ jobs:
       - name: Display Pip Versions
         shell: bash -l {0}
         run: pip list
-      - name: Download "build" folder (cache)
-        uses: dawidd6/action-download-artifact@v9
-        with:
-          workflow: cache.yml
-          branch: main
-          name: build-cache
-          path: _build
+      # - name: Download "build" folder (cache)
+      #   uses: dawidd6/action-download-artifact@v9
+      #   with:
+      #     workflow: cache.yml
+      #     branch: main
+      #     name: build-cache
+      #     path: _build
       # # Build Assets (Download Notebooks and PDF via LaTeX)
       # - name: Build PDF from LaTeX
       #   shell: bash -l {0}