feat(config): add issue templates for Epics, User Stories, and Subtasks

.gitea/ISSUE_TEMPLATE/subtask.md

@@ -0,0 +1,35 @@
+---
+name: "Subtask"
+about: "A smaller task that contributes to a User Story or Epic"
+title: "[Subtask] <Task title>"
+labels: ["Type/Subtask"]
+---
+
+## 🧾 Description
+Briefly describe what needs to be done for this subtask.
+
+---
+
+## 🔗 Linked Issues
+- Parent Story: #<user-story-number>
+- Related Epic: #<epic-number>
+
+---
+
+## ⚙️ Steps / Tasks
+- [ ] Task 1
+- [ ] Task 2
+- [ ] Task 3
+
+---
+
+## ✅ Definition of Done
+What must be true for this subtask to be considered complete:
+- [ ] Code implemented
+- [ ] Tests passed
+- [ ] Reviewed and merged
+
+---
+
+## 🧩 Estimated Size
+Use label: `Size/XS` | `Size/S` | `Size/M` | `Size/L` | `Size/XL`