Create design submission issue template

Added a new issue template for design submissions including fields for designer name, design type, description, and design file/link.

Author: ajay-dhangar

.github/ISSUE_TEMPLATE/design_submission.yml

@@ -0,0 +1,37 @@
+name: 🎨 Design Submission
+description: Submit a design for UI/UX, banners, or branding assets
+title: "[Design]: Asset Name"
+labels:
+  - design
+  - ui/ux
+body:
+  - type: markdown
+    attributes:
+      value: |
+        ## 🎨 Design Submission — CodeHarborHub
+        Submit your creative designs and get featured on our website!
+  - type: input
+    id: designer_name
+    attributes:
+      label: Designer Name
+      placeholder: e.g., Ajay Dhangar
+  - type: dropdown
+    id: design_type
+    attributes:
+      label: Design Type
+      options:
+        - Logo
+        - Website Banner
+        - Event Poster
+        - UI Mockup
+        - Infographic
+  - type: textarea
+    id: description
+    attributes:
+      label: Design Description
+      placeholder: Briefly explain your design and concept.
+  - type: input
+    id: design_link
+    attributes:
+      label: Design File / Link
+      placeholder: e.g., Figma / Canva / Drive / Behance link