JNG-6382 Fix branch references and acronym definitions

- Replace \"checkout main\" with \"checkout master\" in CIFLOW.md and CONTRIBUTING.md
- Fix wrong ESM/ASM/PSM acronym definitions (ESM=Editor Specific Model, ASM=Architecture Specific Model, PSM=Platform Specific Model)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: klm-blzs

.github/CIFLOW.md

@@ -41,7 +41,7 @@ gitGraph
     merge bugfix/JNG-4 id: "merge-fix"
     checkout develop
     merge release/1.0-beta1 id: "merge-release"
-    checkout main
+    checkout master
     merge release/1.0-beta1 id: "release-1.0"
 ```