Reuse held Spine poses and redeploy countdown textures (#434)

docs/history/0.2.3.md

@@ -105,3 +105,13 @@ interface strings. Only its message values are ported; later keys and the pack's
 checklist covering the problem, source evidence, assumptions, actual checks and golden changes. The template
 is installed at `.github/pull_request_template.md`, the default template location, so GitHub can offer it
 without a named-template query parameter. No gameplay rules change.
+
+### 28.8 Stop recalculating held Spine poses — PR #434
+
+Ported from [PR #434](https://github.com/sganggs/Stronghold-Protocol/pull/434) by @Cloudnyco. A finished,
+non-looping, unmixed death pose or frozen model can reuse its posed skeleton and cached pixels while its
+clock advances. First poses, new clips, tint changes, mixing, multiple tracks, pending wind-ups / closing clips,
+clipping switches, dirty textures and zoom rescaling still update. Redeployment resumes normal animation.
+Redeploy countdown labels share rasterized textures keyed by text, colour and resolution; late web fonts refresh
+them in place. The 64 targeted renderer tests passed. The author's performance measurements are not reproduced
+here; real Pixi checks are part of the integration pass. No battle rule or golden result is intentionally changed.