[organization_capital.md] Update np.random → Generator API

[Chihiro2000GitHub]

Summary

This PR migrates legacy NumPy random API usage in organization_capital.md as part of QuantEcon/meta#299.

The lecture already builds a seeded generator in its four simulation functions. This PR brings the one remaining cell, which still used np.random.seed(...) and np.random.randn(...), into line with them.

Related PRs and issues

I checked for open PRs and issues related to this lecture. No open PR modifies organization_capital.md, and no open issue concerns this migration.

While checking the rebuilt figure I did notice that the posterior-mean panel does not show the convergence the text describes. That is pre-existing, and I have filed it separately as #1015.

Details

• In the cell that plots the posterior evolution, np.random.seed(0) → rng = np.random.default_rng(0) and np.random.randn(T) → rng.standard_normal(T).
• The existing seed (0) is kept, and no new seed was introduced.
• The four existing rng = np.random.default_rng(seed) calls elsewhere in the lecture are unchanged.
• No prose changes were needed. The text describes the figure qualitatively: the posterior mean converges to the true value and the posterior uncertainty shrinks at rate 1/sqrt(n).
• The lecture contains no Numba (@jit, @njit, @jitclass, parallel=True, prange) code.
• A full local build completed successfully and organization_capital.md executed without errors.

Note for reviewers

Only the left panel of the posterior figure changes: the posterior standard deviation plotted on the right does not depend on the draws.

Hi @mmcky and @HumphreyYang, I'd be grateful if you could take a look when you have time.

[github-actions]

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📚 Changed Lectures

• organization_capital

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Build Info

• Workflow: Build Project [using jupyter-book]