docs: add feature roadmap

docs/feature-roadmap.md

@@ -17,6 +17,14 @@
 
 ## Phase 1: Feature Area Breakdown
 
+### Overview
+
+Based on analysis of:
+- Existing codebase (Ash resources, LiveViews, controllers)
+- Open issues: https://git.local-it.org/local-it/mitgliederverwaltung/issues
+- Current milestones and sprint planning
+- Architecture documentation
+
 ### Feature Areas
 
 #### 1. **Authentication & Authorization** 🔐
@@ -732,6 +740,12 @@ Since this is a **Phoenix LiveView** application with **Ash Framework**, we have
 
 ---
 
+## Next Steps
+
+- [x] **Phase 1:** Feature area breakdown ✅
+- [x] **Phase 2:** API endpoint definition ✅
+- [ ] **Phase 3:** Create implementation tasks for each endpoint
+- [ ] **Phase 4:** Organize and prioritize tasks with dependencies
 
 ---