feat!: isolate the public ZCode implementation

.github/pull_request_template.md

@@ -1,15 +1,20 @@
+# Pull request
+
 ## Scope
 
 Describe the `zcode_tools/`, `cli-tools/`, `build/`, or documentation surface changed.
 
 ## Validation
 
-- [ ] JSON files valid (`python3 -c "import json,glob; [json.load(open(f)) for f in glob.glob('**/*.json', recursive=True)]"`)
-- [ ] `cli-tools/scripts/install.sh install --marketplace <name> --plan` runs clean
+- [ ] JSON files validate with Python's standard library
+- [ ] Installer plan runs clean for the affected marketplace on macOS and Ubuntu
 - [ ] No `.env` tracked (`git ls-files | grep -E '(^|/)\.env$'` returns nothing)
+- [ ] No development-only agent, test, validation, benchmark, or runtime
+      artifacts added
 - [ ] Targeted smoke/checks for the touched scope
 
 ## Release
 
-- [ ] `build/version.json` and `VERSION` bumped when release behavior changes
+- [ ] The three build-version sources match for release behavior changes
+- [ ] Core-plugin versions match between `marketplace.json` and `plugin.json`
 - [ ] `CHANGELOG.md` entry added for release behavior changes