fix(web): load the inlang plugin from node_modules, not a CDN

`web/project.inlang/settings.json` pointed `modules` at
https://cdn.jsdelivr.net/npm/@inlang/plugin-message-format@4/dist/index.js —
inlang's stock `paraglide-js init` scaffolding, which nobody had a reason to
keep. It made `bun run codegen` need the network at build time, so in a
sandbox that has none (the Nix build; any air-gapped CI) the plugin import
failed and paraglide compiled ZERO messages.

That failure is silent by design: the inlang SDK logs a PluginImportError as a
WARNING, paraglide still prints "Successfully compiled" and exits 0, vite
bundles the empty message set, and the console only dies at request time inside
renderToReadableStream because every `m.foo()` is undefined. Reported from a
NixOS host running punktfunk-web-server.

The plugin is a normal npm package, so depend on it like one: add
@inlang/plugin-message-format as a devDependency and reference it by relative
path. `loadProjectFromDirectory` (which both `paraglide-js compile` and the
vite plugin use) imports non-`http` modules straight off disk, and the shipped
dist/index.js is a self-contained bundle with no imports of its own, so it
loads from the data: URL exactly as the CDN copy did. Compiles 268 messages
offline, with no project.inlang/cache round-trip.

Add tools/check-i18n.mjs, run at the end of `codegen`, so this can never ship
silently again: it fails the build on a remote `modules` entry, a module that
does not resolve, or a compiled message count below what messages/en.json
defines. Verified it catches all three (remote URL, missing plugin, corrupt
plugin that compiles to 0 messages) and passes a healthy build.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packaging/nix/packages.nix

@@ -313,7 +313,7 @@ in
         dontFixup = true;
         outputHashMode = "recursive";
         outputHashAlgo = "sha256";
-        outputHash = "sha256-OA4NjwapsCV/z+0rftDCMAQJGWw63Mi/GARetmuy0QU="; # web/bun.lock deps (refresh on lockfile change; see README).
+        outputHash = "sha256-5oVZv65SMvq9i2REzHE8Pyn6qUZaV2FnPQdaouwcwoU="; # web/bun.lock deps (refresh on lockfile change; see README).
       };
     in
     stdenvNoCC.mkDerivation {
@@ -326,6 +326,14 @@ in
 
       # No cross-derivation dep cache: codegen + the vite build are fully offline (every input is in
       # the vendored node_modules, the checked-in api/openapi.json, and web/project.inlang).
+      #
+      # ⚠ "Offline" is load-bearing and NOT self-enforcing. inlang resolves the plugins in
+      # web/project.inlang/settings.json `modules`, and a failed import is only a WARNING there:
+      # paraglide then prints "Successfully compiled", exits 0, and emits ZERO messages, so the
+      # console builds fine and dies at SSR time with every `m.foo()` undefined. That is exactly
+      # what a CDN URL in `modules` did in this network-less sandbox. The plugin is now a normal
+      # devDependency referenced by path, and `bun run codegen` ends in tools/check-i18n.mjs, which
+      # fails the build on a remote module or a short message count. Keep both properties.
       buildPhase = ''
         runHook preBuild
         export HOME=$TMPDIR

web/bun.lock

@@ -25,6 +25,7 @@
       "devDependencies": {
         "@biomejs/biome": "^2.5.2",
         "@inlang/paraglide-js": "^2.20.2",
+        "@inlang/plugin-message-format": "^4.4.0",
         "@storybook/react-vite": "^10.4.6",
         "@tailwindcss/vite": "^4.3.2",
         "@tanstack/nitro-v2-vite-plugin": "^1.155.0",
@@ -283,6 +284,8 @@
 
     "@inlang/paraglide-js": ["@inlang/paraglide-js@2.20.2", "", { "dependencies": { "@inlang/recommend-sherlock": "^0.2.1", "@inlang/sdk": "^2.10.0", "commander": "11.1.0", "consola": "3.4.0", "json5": "2.2.3", "unplugin": "^2.1.2", "urlpattern-polyfill": "^10.0.0" }, "peerDependencies": { "typescript": ">=5.6" }, "optionalPeers": ["typescript"], "bin": { "paraglide-js": "bin/run.js" } }, "sha512-V8iY3uu/vQU94gEag1bdC3glMJSp4Dg3XMwfnabZLBh1Dv0F++DvDYlMeniqv2+nHbnS/twB75AM140OmpHDEg=="],
 
+    "@inlang/plugin-message-format": ["@inlang/plugin-message-format@4.4.0", "", { "dependencies": { "flat": "^6.0.1" } }, "sha512-n4aXt6XVg5kxhKoLAhi9nMgZtCA9iS0QOaXte56VqxWHcfj9O4c4gOkyVQZH7H9D8h7OZufCrO1sZGYOypPwEA=="],
+
     "@inlang/recommend-sherlock": ["@inlang/recommend-sherlock@0.2.1", "", { "dependencies": { "comment-json": "^4.2.3" } }, "sha512-ckv8HvHy/iTqaVAEKrr+gnl+p3XFNwe5D2+6w6wJk2ORV2XkcRkKOJ/XsTUJbPSiyi4PI+p+T3bqbmNx/rDUlg=="],
 
     "@inlang/sdk": ["@inlang/sdk@2.10.2", "", { "dependencies": { "@lix-js/sdk": "0.4.10", "@sinclair/typebox": "^0.31.17", "kysely": "^0.28.12", "sqlite-wasm-kysely": "0.3.0", "uuid": "^14.0.0" } }, "sha512-O1ki72SNK6LPagaGrvlioBb1mWKvump7cO7P85hfGZjdFTmDdn3icI0A6MvaBsB3P9KQHAjzyubnN1OslGufTw=="],
@@ -1383,6 +1386,8 @@
 
     "find-up": ["find-up@8.0.0", "", { "dependencies": { "locate-path": "^8.0.0", "unicorn-magic": "^0.3.0" } }, "sha512-JGG8pvDi2C+JxidYdIwQDyS/CgcrIdh18cvgxcBge3wSHRQOrooMD3GlFBcmMJAN9M42SAZjDp5zv1dglJjwww=="],
 
+    "flat": ["flat@6.0.1", "", { "bin": { "flat": "cli.js" } }, "sha512-/3FfIa8mbrg3xE7+wAhWeV+bd7L2Mof+xtZb5dRDKZ+wDvYJK4WDYeIOuOhre5Yv5aQObZrlbRmk3RTSiuQBtw=="],
+
     "focus-trap": ["focus-trap@7.5.4", "", { "dependencies": { "tabbable": "^6.2.0" } }, "sha512-N7kHdlgsO/v+iD/dMoJKtsSqs5Dz/dXZVebRgJw23LDk+jMi/974zyiOYDziY2JPp8xivq9BmUGwIJMiuSBi7w=="],
 
     "foreground-child": ["foreground-child@3.3.1", "", { "dependencies": { "cross-spawn": "^7.0.6", "signal-exit": "^4.0.1" } }, "sha512-gIXjKqtFuWEgzFRJA9WCQeSJLZDjgJUOMCMzxtvFq/37KojM1BFGufqsCy0r4qSQmYLsZYMeyRqzIWOMup03sw=="],

web/package.json

@@ -5,7 +5,7 @@
 	"description": "punktfunk management console — TanStack Start + React Query (orval) + @unom/ui + Paraglide i18n",
 	"scripts": {
 		"prepare": "bun run codegen",
-		"codegen": "orval --config orval.config.ts && paraglide-js compile --project ./project.inlang --outdir ./src/paraglide",
+		"codegen": "orval --config orval.config.ts && paraglide-js compile --project ./project.inlang --outdir ./src/paraglide && node tools/check-i18n.mjs",
 		"predev": "orval --config orval.config.ts",
 		"dev": "vite dev --port 47992",
 		"prebuild": "orval --config orval.config.ts",
@@ -39,6 +39,7 @@
 	"devDependencies": {
 		"@biomejs/biome": "^2.5.2",
 		"@inlang/paraglide-js": "^2.20.2",
+		"@inlang/plugin-message-format": "^4.4.0",
 		"@storybook/react-vite": "^10.4.6",
 		"@tailwindcss/vite": "^4.3.2",
 		"@tanstack/nitro-v2-vite-plugin": "^1.155.0",

web/project.inlang/settings.json

@@ -2,9 +2,7 @@
   "$schema": "https://inlang.com/schema/project-settings",
   "baseLocale": "en",
   "locales": ["en", "de"],
-  "modules": [
+  "modules": ["./node_modules/@inlang/plugin-message-format/dist/index.js"],
-    "https://cdn.jsdelivr.net/npm/@inlang/plugin-message-format@4/dist/index.js"
-  ],
   "plugin.inlang.messageFormat": {
     "pathPattern": "./messages/{locale}.json"
   }

web/tools/check-i18n.mjs

@@ -0,0 +1,80 @@
+// Guard: assert paraglide actually compiled our translations.
+//
+// The inlang SDK treats a failed plugin import as a WARNING, not an error: if the
+// message-format plugin can't be loaded, `paraglide-js compile` still prints
+// "Successfully compiled" and exits 0 — having emitted an empty message set. vite
+// then happily bundles that, and the console only dies at SSR time, deep inside
+// renderToReadableStream, because every `m.foo()` is undefined. That shipped once
+// (a Nix build, where the plugin was fetched from a CDN in a network-off sandbox),
+// so the build now fails loudly instead.
+//
+//   node tools/check-i18n.mjs          # run from web/, after `paraglide-js compile`
+//
+// Env knobs: PARAGLIDE_OUTDIR (default ./src/paraglide), INLANG_PROJECT (default
+// ./project.inlang).
+
+import { existsSync, readdirSync, readFileSync } from "node:fs";
+import { join, resolve } from "node:path";
+
+const outdir = resolve(process.env.PARAGLIDE_OUTDIR ?? "./src/paraglide");
+const project = resolve(process.env.INLANG_PROJECT ?? "./project.inlang");
+
+const fail = (msg) => {
+	console.error(`ERROR: i18n check failed — ${msg}`);
+	process.exit(1);
+};
+
+const settingsPath = join(project, "settings.json");
+if (!existsSync(settingsPath)) fail(`no inlang settings at ${settingsPath}`);
+const settings = JSON.parse(readFileSync(settingsPath, "utf8"));
+
+// Every plugin must resolve offline. A remote module makes the build depend on a CDN
+// at compile time, which silently yields zero messages in any sandbox without network
+// (Nix, air-gapped CI) — see the header.
+for (const mod of settings.modules ?? []) {
+	if (/^https?:/i.test(mod)) {
+		fail(
+			`inlang module "${mod}" is a remote URL — vendor it as a devDependency and reference it by path, ` +
+				`else offline builds compile zero messages`,
+		);
+	}
+	const modPath = resolve(project, "..", mod);
+	if (!existsSync(modPath))
+		fail(
+			`inlang module "${mod}" does not exist at ${modPath} (run \`bun install\`?)`,
+		);
+}
+
+// The base-locale source file is the source of truth for how many messages we expect.
+const pathPattern = settings["plugin.inlang.messageFormat"]?.pathPattern;
+if (!pathPattern)
+	fail("settings.json has no plugin.inlang.messageFormat.pathPattern");
+const basePath = resolve(
+	project,
+	"..",
+	pathPattern.replace("{locale}", settings.baseLocale),
+);
+if (!existsSync(basePath)) fail(`base-locale messages missing at ${basePath}`);
+const expected = Object.keys(JSON.parse(readFileSync(basePath, "utf8"))).filter(
+	(k) => !k.startsWith("$"),
+).length;
+if (expected === 0) fail(`base-locale messages at ${basePath} are empty`);
+
+const messagesDir = join(outdir, "messages");
+if (!existsSync(messagesDir))
+	fail(`paraglide emitted no messages dir at ${messagesDir}`);
+// paraglide writes one module per message plus an `_index.js` barrel.
+const emitted = readdirSync(messagesDir).filter(
+	(f) => f.endsWith(".js") && f !== "_index.js",
+).length;
+
+if (emitted < expected) {
+	fail(
+		`paraglide emitted ${emitted} messages but ${basePath} defines ${expected}. ` +
+			`The message-format plugin most likely failed to import — check the compile output for PluginImportError.`,
+	);
+}
+
+console.log(
+	`✔ i18n check: ${emitted} compiled messages for ${settings.locales.join(", ")}`,
+);