Architectural Refactoring (#3)

* refactor: implement layered architecture with separation of responsibilities

- remove monolithic index.ts in favor of a modular structure
- implement config.ts for centralized configuration and types
- create a services/ layer for isolating business logic
- establish a dependency injection pattern for testability
- maintain core branch creation functionality with better separation

* build: update distribution artifacts to modular architecture

- updates package.json to reflect changes in the entry point
- generates compiled javascript corresponding to the new layered structure
- maintains compatibility with the github actions runtime environment
- preserves the action's external api while remaining internally modular

* documenting...

Author: rmottanet

README.md

@@ -36,7 +36,7 @@ jobs:
       contents: write # Required for creating branches/references
     steps:
       - name: Create 'release/v1.2.0' branch from 'main'
-        uses: ws2git/branch-spawn@v1
+        uses: ws2git/branch-spawn@v2
         with:
           # **ADJUST INPUTS HERE**
           owner: ${{ github.repository_owner }} # Or a specific organization/user name