chore(deps): bump node from 22-alpine to 26-alpine in /docs

Bumps node from 22-alpine to 26-alpine.

---
updated-dependencies:
- dependency-name: node
  dependency-version: 26-alpine
  dependency-type: direct:production
...

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

Author: dependabot[bot]

docs/Dockerfile

@@ -3,7 +3,7 @@
 # The build context is `docs/` only — this package is a self-contained pnpm
 # workspace (its own pnpm-workspace.yaml + pnpm-lock.yaml), fully decoupled from
 # the monorepo workspace and the app build.
-FROM node:22-alpine@sha256:9385cd9f3001dfc3431e8ead12c43e9e1f87cc1b9b5c6cfd0f73865d405b27c4 AS build
+FROM node:26-alpine@sha256:9c0e1e52125d6b67d505cf75b4880fcf1290ccea5c480849910e1d57b2cf72b5 AS build
 WORKDIR /app
 RUN npm install -g pnpm@11.1.2
 COPY package.json pnpm-lock.yaml pnpm-workspace.yaml ./