chore(deps): bump node in /docker in the docker group across 1 directory

Bumps the docker group with 1 update in the /docker directory: node.


Updates `node` from 22-bookworm-slim to 26-bookworm-slim

---
updated-dependencies:
- dependency-name: node
  dependency-version: 26-bookworm-slim
  dependency-type: direct:production
  dependency-group: docker
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

docker/Dockerfile

@@ -1,6 +1,6 @@
 # Keep the Docker base on Node 22 because the official Node 24/25 slim images
 # no longer publish linux/arm/v7 manifests, which breaks our armv7 Docker jobs.
-FROM node:22-bookworm-slim AS builder
+FROM node:26-bookworm-slim AS builder
 
 WORKDIR /app
 
@@ -18,7 +18,7 @@ COPY . .
 RUN npm run build:web && npm run build:server
 RUN npm prune --omit=dev --no-audit --no-fund
 
-FROM node:22-bookworm-slim
+FROM node:26-bookworm-slim
 
 WORKDIR /app