chore: bump version to 4.5.0 (#60)

Release-prep bump across all four plugin manifests (Claude Code, Codex,
Gemini, Copilot) for v4.5.0. The cross-manifest parity test keeps them aligned.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.github/plugin/plugin.json

@@ -1,7 +1,7 @@
 {
   "name": "ponytail",
   "description": "Lazy senior dev mode. Forces the simplest, shortest solution that actually works: YAGNI, stdlib first, no unrequested abstractions.",
-  "version": "4.4.0",
+  "version": "4.5.0",
   "author": {
     "name": "Dietrich Gebert",
     "url": "https://github.com/DietrichGebert"