chore(deploy): add deploy.sh remote script, update Makefile

- deploy.sh: SSH-triggered deploy for prod and test environments on
  srv-nyx (linode.oneskyit.com). Pulls repos, builds ae_app container
  with correct BUILD_MODE, restarts ae_api.
- Makefile: rename build-ui → build-docker-dev/test/prod to match new
  naming convention; add deploy-remote-test and deploy-remote-prod targets
- .env.default: AE_APP_BUILD_MODE staging → dev (from prior session)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Makefile

@@ -1,7 +1,7 @@
 # Aether Platform - Operations Makefile
 # Use these shortcuts for faster development and deployment.
 
-.PHONY: up down restart-api build-api build-ui logs ps
+.PHONY: up down restart-api build-api build-docker-dev build-docker-test build-docker-prod logs ps deploy-remote-test deploy-remote-prod
 
 # Start the entire stack
 up:
@@ -21,10 +21,18 @@ restart-api:
 build-api:
 	docker compose up -d --build ae_api
 
-# REBUILD UI: Standard autonomous build for SvelteKit
-build-ui:
+# BUILD DOCKER UI: Build the SvelteKit container for the given mode.
+# Use 'npm run dev' for active development (Vite HMR, no Docker).
+# Use these only when testing the production-like Docker build locally.
+build-docker-dev:
 	docker compose build ae_app && docker compose up -d ae_app
 
+build-docker-test:
+	docker compose build --build-arg BUILD_MODE=test ae_app && docker compose up -d ae_app
+
+build-docker-prod:
+	docker compose build --build-arg BUILD_MODE=prod ae_app && docker compose up -d --remove-orphans ae_app
+
 # View combined logs
 logs:
 	docker compose logs -f --tail=100
@@ -32,3 +40,11 @@ logs:
 # Check service status
 ps:
 	docker compose ps
+
+# Remote deploy (SSH to linode.oneskyit.com, run deploy.sh)
+# Requires key-based SSH and deploy.sh committed + pulled on the server.
+deploy-remote-test:
+	ssh linode.oneskyit.com 'bash /srv/env/test_aether/deploy.sh test'
+
+deploy-remote-prod:
+	ssh linode.oneskyit.com 'bash /srv/env/prod_aether/deploy.sh prod'