chore(frontend): QR code for dev --host and /api proxy

- Add vite-plugin-qrcode so `yarn dev --host` prints a scannable QR for the
  LAN URL.
- Proxy /api to the backend in dev so the frontend can use same-origin
  relative URLs (VITE_API_URL=""), which keeps the dashboard reachable from
  other LAN devices instead of their own localhost.

Author: eetu

frontend/package.json

@@ -45,6 +45,7 @@
     "typescript-eslint": "^8.60.1",
     "unplugin-auto-import": "^21.0.0",
     "vite": "^8.0.16",
+    "vite-plugin-qrcode": "^0.4.1",
     "vite-tsconfig-paths": "^6.1.1",
     "vitest": "^4.1.8",
     "vitest-browser-react": "^2.2.0"

frontend/vite.config.ts

@@ -1,9 +1,19 @@
 import react from "@vitejs/plugin-react";
 import AutoImport from "unplugin-auto-import/vite";
 import { defineConfig } from "vite";
+import { qrcode } from "vite-plugin-qrcode";
 
 // https://vitejs.dev/config/
 export default defineConfig({
+  // Proxy API calls to the backend so the frontend can use same-origin relative
+  // URLs (VITE_API_URL=""). This keeps `yarn dev --host` working from other LAN
+  // devices — the request hits this dev server's IP and is forwarded here to the
+  // backend on localhost, instead of the device trying its own localhost:3000.
+  server: {
+    proxy: {
+      "/api": { target: "http://localhost:3000", changeOrigin: true },
+    },
+  },
   plugins: [
     react({
       jsxImportSource: "@emotion/react",
@@ -15,5 +25,7 @@ export default defineConfig({
       imports: ["vitest"],
       dts: true,
     }),
+    // Print a scannable QR code for the LAN URL with `yarn dev --host`.
+    qrcode(),
   ],
 });

frontend/yarn.lock

@@ -4027,6 +4027,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"uqr@npm:^0.1.2":
+  version: 0.1.3
+  resolution: "uqr@npm:0.1.3"
+  checksum: 10/cde1dd270e3d39fc1870375d33a88c1ec7ac430c6e1b0b28943ad08b029dc9409076aa2213ebf2eb209cfa37abccca365d85f2cd3b1cdefbcfb68ab8c18857d3
+  languageName: node
+  linkType: hard
+
 "uri-js@npm:^4.2.2":
   version: 4.4.1
   resolution: "uri-js@npm:4.4.1"
@@ -4063,6 +4070,17 @@ __metadata:
   languageName: node
   linkType: hard
 
+"vite-plugin-qrcode@npm:^0.4.1":
+  version: 0.4.1
+  resolution: "vite-plugin-qrcode@npm:0.4.1"
+  dependencies:
+    uqr: "npm:^0.1.2"
+  peerDependencies:
+    vite: ">=3"
+  checksum: 10/dd11488c2a038a4a6f7118e8eef5d825f3f3367c6ee2e0af432b2763eb2a83f104793b0376211d8cd7cb47866b8a191518477ba34f6c826e2820d700ba21e90c
+  languageName: node
+  linkType: hard
+
 "vite-tsconfig-paths@npm:^6.1.1":
   version: 6.1.1
   resolution: "vite-tsconfig-paths@npm:6.1.1"
@@ -4220,6 +4238,7 @@ __metadata:
     unplugin-auto-import: "npm:^21.0.0"
     usehooks-ts: "npm:^3.1.1"
     vite: "npm:^8.0.16"
+    vite-plugin-qrcode: "npm:^0.4.1"
     vite-tsconfig-paths: "npm:^6.1.1"
     vitest: "npm:^4.1.8"
     vitest-browser-react: "npm:^2.2.0"