fix: staging to generate stubs as needed (#366)

desktop/biome.json

@@ -1,5 +1,5 @@
 {
-  "$schema": "https://biomejs.dev/schemas/2.4.6/schema.json",
+  "$schema": "https://biomejs.dev/schemas/2.4.11/schema.json",
   "vcs": {
     "enabled": true,
     "clientKind": "git",

justfile

@@ -166,6 +166,11 @@ staging *ARGS:
     set -euo pipefail
     cd {{desktop_dir}}
     pnpm install
+    # Ensure sidecar placeholder binaries exist (Tauri validates externalBin at compile time)
+    TARGET=$(rustc -vV | sed -n 's|host: ||p')
+    mkdir -p src-tauri/binaries
+    touch "src-tauri/binaries/sprout-acp-$TARGET"
+    touch "src-tauri/binaries/sprout-mcp-server-$TARGET"
     cd ..
     cargo build --release -p sprout-acp -p sprout-mcp
     cd {{desktop_dir}}