Merge main into cake eating refactor PR

Resolved conflict in _toc.yml by:
- Accepting the new "Optimal Growth" section from main
- Using renamed file "cake_eating" instead of "cake_eating_problem"
- Keeping Household Problems section with only cake eating lectures

The main branch had moved Cass-Koopmans lectures to a separate "Optimal Growth" section, which is preserved in this merge.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: jstac

lectures/_toc.yml

@@ -72,14 +72,9 @@ parts:
   - file: jv
   - file: mccall_q
   - file: odu
-- caption: Consumption, Savings and Capital
+- caption: Household Problems
   numbered: true
   chapters:
-  - file: cass_koopmans_1
-  - file: cass_koopmans_2
-  - file: cass_fiscal
-  - file: cass_fiscal_2
-  - file: ak2
   - file: cake_eating
   - file: cake_eating_numerical
   - file: cake_eating_stochastic
@@ -96,6 +91,14 @@ parts:
   - file: perm_income
   - file: perm_income_cons
   - file: lq_inventories
+- caption: Optimal Growth
+  numbered: true
+  chapters:
+  - file: cass_koopmans_1
+  - file: cass_koopmans_2
+  - file: cass_fiscal
+  - file: cass_fiscal_2
+  - file: ak2
 - caption: Multiple Agent Models
   numbered: true
   chapters:
@@ -130,4 +133,4 @@ parts:
   chapters:
   - file: troubleshooting
   - file: zreferences
-  - file: status
+  - file: status