[documentation] Reproduction: Towers et al. 2024 — optimal height-growth & water availability

[dfalster]

Goal

Add a Reproductions post that re-creates a key figure from Towers et al.
(2024), as both documentation and a living regression check.

Not in the original traitecoevo/plant#209 list, but added here as a strong
reproduction candidate: it uses an optimal height-growth framework closely
related to plant to predict trait responses to water availability.

Reference

• Towers, I. R., O'Reilly-Nugent, A., Sabot, M. E. B., Vesk, P. A., &
  Falster, D. S. (2024).
  Optimising height-growth predicts trait responses to water availability
  and other environmental drivers.
  Plant, Cell & Environment, 47(12), 4849–4869.
• DOI: https://doi.org/10.1111/pce.15042
• Publisher link:
  https://onlinelibrary.wiley.com/doi/abs/10.1111/pce.15042

What's needed

• Choose the target figure(s) — the predicted trait-vs-water-availability
  optima are the headline results.
• Confirm whether this relies on the TF24 strategy / leaf-hydraulics
  branch of plant; if so, pin with plant-ref/plant-sha rather than
  a release. (Relates to overstorey#1 and overstorey#2 on the TF24 leaf
  model.)
• Copy posts/_reproduction-template/ → posts/<date>-towers2024-water/
  and fill the paper: front-matter block.
• Locate the original figure-generation repo and pin it
  (code-repo / code-ref / code-entrypoint); leave TODO until the
  publication commit is confirmed.
• Transcribe the source parameters (traits, water-availability gradient)
  into the visible params block.
• Render, set fidelity: to the verdict, commit _freeze/ + renv.lock.

See posts/reproductions.qmd and paper-code/README.md for the workflow.
Related: traitecoevo/plant#209.