Fix healthcheck: use bun instead of missing wget

The oven/bun:1 base image's default HEALTHCHECK uses wget, which isn't
installed. Override with a bun-based HTTP check in the compose file.
Also fix pre-commit hook to fall back to npx when bun is unavailable.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.husky/pre-commit

@@ -2,4 +2,4 @@
 export BUN_INSTALL="$HOME/.bun"
 export PATH="$BUN_INSTALL/bin:$PATH"
 
-bun lint-staged
+bun lint-staged 2>/dev/null || npx lint-staged

docker-compose.aggregator.yml

@@ -9,6 +9,12 @@ services:
       dockerfile: Dockerfile.aggregator
     container_name: backlog-aggregator
     restart: unless-stopped
+    healthcheck:
+      test: ["CMD", "bun", "-e", "fetch('http://127.0.0.1:6420/').then(r => process.exit(r.ok ? 0 : 1)).catch(() => process.exit(1))"]
+      interval: 30s
+      timeout: 10s
+      start_period: 60s
+      retries: 3
     volumes:
       # Mount all project directories that contain backlog folders
       - /opt/websites:/projects/websites:rw