chore: update dev script and add ADB download helper

dev.sh now runs preflight checks (build backend, build desktop,
wails generate module, npm install + tsc) before starting wails dev,
so type errors and binding mismatches surface immediately. Adds
download-adb.sh for fetching platform ADB binaries to embed in
distribution builds.

scripts/dev.sh

@@ -2,20 +2,35 @@
 set -e
 
 ROOT="$(cd "$(dirname "$0")/.." && pwd)"
-
-echo "[DroidScope] Starting dev environment..."
-
-cd "$ROOT/frontend-react"
-npm run dev &
-FRONTEND_PID=$!
-
-cd "$ROOT/desktop"
 export PATH="$PATH:$(go env GOPATH)/bin"
-wails dev &
-WAILS_PID=$!
 
-echo "[DroidScope] Frontend PID: $FRONTEND_PID"
-echo "[DroidScope] Wails PID:    $WAILS_PID"
+# ── 1. Build backend-go ────────────────────────────────────────────────────────
+echo "[1/4] Building backend-go..."
+cd "$ROOT/backend-go"
+go build ./...
+echo "      ✓ backend-go"
 
-trap "kill $FRONTEND_PID $WAILS_PID 2>/dev/null; exit 0" INT TERM
-wait
+# ── 2. Build desktop (Go) ──────────────────────────────────────────────────────
+echo "[2/4] Building desktop..."
+cd "$ROOT/desktop"
+go build ./...
+echo "      ✓ desktop"
+
+# ── 3. Regenerate Wails JS bindings ───────────────────────────────────────────
+echo "[3/4] Regenerating Wails bindings..."
+cd "$ROOT/desktop"
+wails generate module
+echo "      ✓ wailsjs"
+
+# ── 4. Install & type-check frontend ──────────────────────────────────────────
+echo "[4/4] Checking frontend..."
+cd "$ROOT/frontend-react"
+npm install --silent
+npx tsc -b --noEmit
+echo "      ✓ frontend"
+
+# ── Start dev ─────────────────────────────────────────────────────────────────
+echo ""
+echo "Starting Wails dev server..."
+cd "$ROOT/desktop"
+wails dev

scripts/download-adb.sh

@@ -0,0 +1,56 @@
+#!/usr/bin/env bash
+# Downloads ADB binaries for all platforms into desktop/internal/adbembed/bin/
+# Run once before building for distribution.
+set -e
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+BIN_DIR="$ROOT/desktop/internal/adbembed/bin"
+TMP=$(mktemp -d)
+
+echo "[DroidScope] Downloading platform-tools..."
+
+download_and_extract() {
+  local os=$1
+  local url=$2
+  local src_name=$3
+  local dest_name=$4
+
+  echo "  → $os"
+  if [[ "$url" == *.zip ]]; then
+    curl -fsSL "$url" -o "$TMP/${os}.zip"
+    unzip -q "$TMP/${os}.zip" "platform-tools/$src_name" -d "$TMP/${os}/"
+  else
+    curl -fsSL "$url" -o "$TMP/${os}.tar.gz"
+    tar -xzf "$TMP/${os}.tar.gz" -C "$TMP/${os}/" "platform-tools/$src_name" 2>/dev/null || \
+      tar -xzf "$TMP/${os}.tar.gz" -C "$TMP/${os}/"
+  fi
+
+  cp "$TMP/${os}/platform-tools/$src_name" "$BIN_DIR/$dest_name"
+  chmod +x "$BIN_DIR/$dest_name"
+}
+
+mkdir -p "$TMP/darwin" "$TMP/linux" "$TMP/windows"
+
+download_and_extract \
+  darwin \
+  "https://dl.google.com/android/repository/platform-tools-latest-darwin.zip" \
+  "adb" \
+  "adb-darwin-arm64"
+
+cp "$BIN_DIR/adb-darwin-arm64" "$BIN_DIR/adb-darwin-amd64"
+
+download_and_extract \
+  linux \
+  "https://dl.google.com/android/repository/platform-tools-latest-linux.zip" \
+  "adb" \
+  "adb-linux-amd64"
+
+download_and_extract \
+  windows \
+  "https://dl.google.com/android/repository/platform-tools-latest-windows.zip" \
+  "adb.exe" \
+  "adb-windows-amd64.exe"
+
+rm -rf "$TMP"
+echo "[DroidScope] ADB binaries downloaded to $BIN_DIR"
+ls -lh "$BIN_DIR"