fix: bump Dockerfile to node:22-alpine for node:sqlite support

node:sqlite built-in module requires Node >= 22.5.0; the previous
node:20-alpine image threw ERR_UNKNOWN_BUILTIN_MODULE at startup.

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

Dockerfile

@@ -1,5 +1,5 @@
 # ---- Build stage ----
-FROM node:20-alpine AS builder
+FROM node:22-alpine AS builder
 
 WORKDIR /app
 
@@ -10,7 +10,7 @@ COPY . .
 RUN npm run build
 
 # ---- Production stage ----
-FROM node:20-alpine AS runner
+FROM node:22-alpine AS runner
 
 WORKDIR /app