fix(build): write a trailing newline from the JSON generators (#1246)

The config sync job on v2 failed because `bun run config:env` rewrites
config/custom-environment-variables.json without a trailing newline, and the
pre-commit hook now runs Biome, which wants one. The committed file only had
that newline because Prettier used to add it on the way past, so nothing
noticed until Prettier went away.

Fixing it in the generators rather than teaching Biome to ignore the file:
these are text files and should end with a newline regardless of who is
checking them. The same bug was sitting in three other generators, including
the locales one, whose job also commits its output and would have failed the
same way the first time it ran.

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

Author: TurtIeSocks

packages/config/lib/scripts/genEnvConfig.js

@@ -31,7 +31,7 @@ const generateEnvConfig = async () => {
     resolve(
       `${__dirname}/../../../../config/custom-environment-variables.json`,
     ),
-    JSON.stringify(recursiveObjCheck(sourceConfig), null, 2),
+    `${JSON.stringify(recursiveObjCheck(sourceConfig), null, 2)}\n`,
   )
 }
 

packages/locales/lib/missing.js

@@ -41,7 +41,7 @@ async function missingAll() {
             ? fileName.replace('.json', '.js')
             : fileName,
         ),
-        JSON.stringify(missingKeys, null, 2),
+        `${JSON.stringify(missingKeys, null, 2)}\n`,
       )
       log.info(TAGS.locales, fileName, 'file saved.')
     }),

packages/locales/lib/utils.js

@@ -67,10 +67,11 @@ function readLocaleDirectory(human = false) {
 async function writeJson(translations, ...directories) {
   try {
     const resolved = resolve(...directories)
-    const file =
+    const contents =
       typeof translations === 'string'
         ? translations
         : JSON.stringify(translations, null, 2)
+    const file = contents.endsWith('\n') ? contents : `${contents}\n`
 
     await fs.writeFile(resolved, file, 'utf8')
     log.info(TAGS.locales, 'wrote file', `${resolved.split('/').pop()}`)

packages/masterfile/lib/index.js

@@ -69,7 +69,7 @@ const generate = async (save = false, historicRarity = {}, dbRarity = {}) => {
   if (save) {
     await fs.promises.writeFile(
       resolve(`${__dirname}/data/masterfile.json`),
-      JSON.stringify(newMf, null, 2),
+      `${JSON.stringify(newMf, null, 2)}\n`,
       'utf8',
     )
   }