fix: migrate deployment from Hetzner to Coolify (#1)

## Summary
- Add Coolify deployment configuration (docker-compose, healthchecks, network setup)
- Replace deploy-hetzner CI job with Coolify webhook deploy
- Externalize postgres, qdrant, S3 for Coolify environment
- Remove services not needed for SDK deployment (voice, jitsi, synapse)

## All changes since branch creation
- Coolify docker-compose with healthchecks for all services
- CI pipeline: deploy-hetzner → deploy-coolify (simple webhook curl)
- QDRANT_API_KEY support in rag-service
- Alpine-compatible Dockerfile fixes

Co-authored-by: Sharang Parnerkar <parnerkarsharang@gmail.com>
Reviewed-on: #1

admin-core/Dockerfile

@@ -18,6 +18,9 @@ ARG NEXT_PUBLIC_API_URL
 # Set environment variables for build
 ENV NEXT_PUBLIC_API_URL=$NEXT_PUBLIC_API_URL
 
+# Ensure public directory exists
+RUN mkdir -p public
+
 # Build the application
 RUN npm run build
 
@@ -30,8 +33,8 @@ WORKDIR /app
 ENV NODE_ENV=production
 
 # Create non-root user
-RUN addgroup --system --gid 1001 nodejs
-RUN adduser --system --uid 1001 nextjs
+RUN addgroup -S -g 1001 nodejs
+RUN adduser -S -u 1001 -G nodejs nextjs
 
 # Copy built assets
 COPY --from=builder /app/public ./public