Add JAX implementation to ifp_advanced lecture (#705)

* Add JAX implementation to ifp_advanced lecture

- Renamed "Implementation" section to "Numba Implementation"
- Added new "JAX Implementation" section before "Exercises"
- Implemented IFP_JAX as NamedTuple for JAX JIT compatibility
- Created global utility functions (u_prime, u_prime_inv, R, Y)
- Added create_ifp_jax() factory function
- Implemented K_jax Coleman-Reffett operator with JAX
- Added solve_model_time_iter_jax solver
- Included comparison section showing Numba vs JAX solutions
- Configured JAX for 64-bit precision
- Fixed import conflicts between numba.jit and jax.jit

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

Co-Authored-By: Claude <noreply@anthropic.com>

* Improve code explanations in ifp_advanced lecture

- Add bridging text connecting mathematical equations to code implementation
- Add detailed code walkthrough for Coleman-Reffett operator
- Add explanation of solver function and convergence
- Add economic interpretation of default parameters
- Expand interpretation of consumption policy results
- Fix grammatical errors (comma splice, missing period)
- Rename variables for clarity: a_in→ae_vals, σ_in→c_vals, a_out→ae_out, σ_out→c_out

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

Co-Authored-By: Claude <noreply@anthropic.com>

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Co-authored-by: Claude <noreply@anthropic.com>

Author: jstac