Disable unreliable Gitea Godot cache steps

Gitea cache restores were inconsistent and cache saves timed out or were
rejected as reserved by another job. Remove the cache steps and keep direct
4.7.2 downloads; document the evaluation and when to retry. The workflow is
otherwise clean (no .github/ci.yml exists).

CHANGELOG.md

@@ -10,8 +10,8 @@ Semantic Versioning.
 
 - Unified the project, local tooling and CI/release environment on Godot 4.7.2,
   including matching export templates and project feature metadata.
-- Added Gitea Actions cache for the Godot binary and export templates to reduce
-  repeated download time.
+- Evaluated Gitea Actions cache for the Godot binary/templates; disabled it after
+  cache saves timed out or were rejected, pending a healthy host cache service.
 - Updated release and setup documentation for the 4.7.2 baseline.
 
 ## [0.9.0] — 2026-11-01