feat: change g a default behavior to --no-edit

- 'g a' now keeps original commit message by default (--no-edit)
- Added '--edit' flag to generate new AI commit message
- Simpler workflow for quick amendments
- Updated all documentation
- Bumped version to 0.6.5

package.json

@@ -1,6 +1,6 @@
 {
   "name": "gims",
-  "version": "0.6.4",
+  "version": "0.6.5",
   "description": "Git Made Simple – AI‑powered git helper using Gemini / OpenAI",
   "author": "S41R4J",
   "license": "MIT",