Update Node.js version requirement to v20.12.0 minimum

- Update package.json engines to require Node >=20.12.0
- Update Dockerfile to use node:20.12.0-slim base image
- Update Dockerfile.base to use node:20.12.0 base image
- Ensures consistent Node.js version across all environments

Dockerfile

@@ -6,7 +6,7 @@ ARG APP_PATH
 WORKDIR $APP_PATH
 
 # ---
-FROM node:22-slim AS runner
+FROM node:20.12.0-slim AS runner
 
 LABEL org.opencontainers.image.source="https://github.com/outline/outline"
 

Dockerfile.base

@@ -1,5 +1,5 @@
 ARG APP_PATH=/opt/outline
-FROM node:22 AS deps
+FROM node:20.12.0 AS deps
 
 ARG APP_PATH
 WORKDIR $APP_PATH

package.json

@@ -41,7 +41,7 @@
     "url": "https://github.com/sponsors/outline"
   },
   "engines": {
-    "node": "20 || 22"
+    "node": ">=20.12.0"
   },
   "repository": {
     "type": "git",