feat: turbostarter boilerplate

Production-ready Next.js boilerplate with:
- Runtime env validation (fail-fast on missing vars)
- Feature-gated config (S3, Stripe, email, OAuth)
- Docker + Coolify deployment pipeline
- PostgreSQL + pgvector, MinIO S3, Better Auth
- TypeScript strict mode (no ignoreBuildErrors)
- i18n (en/es), AI modules, billing, monitoring

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.github/ISSUE_TEMPLATE/feature_request.yml

@@ -0,0 +1,35 @@
+name: "Feature request"
+description: Suggest an idea for this project
+title: "[Feature]: "
+labels: ["request"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        ### Thanks for taking the time to create a feature request! Please search open/closed issues before submitting, as the issue may have already been reported/addressed.
+
+  - type: markdown
+    attributes:
+      value: |
+        #### If you aren't sure this is a bug or not, please open a discussion instead:
+        - [Discussions](https://github.com/turbostarter/core/discussions/new?category=general)
+
+  - type: textarea
+    id: feature-description
+    attributes:
+      label: Feature description
+      description: Tell us about your feature request
+      placeholder: "I think this feature would be great because..."
+      value: "Describe your feature request..."
+    validations:
+      required: true
+
+  - type: textarea
+    id: context
+    attributes:
+      label: Additional Context
+      description: Add any other context about the feature here.
+      placeholder: ex. screenshots, Stack Overflow links, forum links, etc.
+      value: "Additional details here..."
+    validations:
+      required: false