feat: automate node-pty prebuild installation

Add postinstall script that automatically downloads node-pty prebuilt
binaries after bun install. This eliminates the manual step developers
previously had to run.

Why this is needed:
- Bun blocks npm postinstall scripts by default for security
- node-pty requires native .node binaries compiled for specific ABIs
- Without prebuilds, terminals don't work in packaged Electron app

How it works:
- scripts/postinstall.sh runs after bun install (via Makefile)
- Detects node or bun in PATH (with fallback to common locations)
- Runs prebuild-install to download binaries from GitHub releases
- Checks for build/Release/pty.node to verify success
- Gracefully degrades if download fails (build continues)

Benefits:
- No manual steps for developers after git pull + bun install
- Works with bun, node, or npm as package manager
- Caches downloads in ~/.npm/_prebuilds for faster reinstalls
- Clear error messages if manual intervention needed

Author: sreya

Makefile

@@ -90,6 +90,8 @@ all: build
 node_modules/.installed: package.json bun.lock
 	@echo "Dependencies out of date or missing, running bun install..."
 	@bun install
+	@echo "Running postinstall scripts..."
+	@./scripts/postinstall.sh
 	@touch node_modules/.installed
 
 # Legacy target for backwards compatibility

package.json

@@ -16,6 +16,7 @@
     "access": "public"
   },
   "scripts": {
+    "postinstall": "./scripts/postinstall.sh",
     "dev": "make dev",
     "prebuild:main": "./scripts/generate-version.sh",
     "build": "make build",

scripts/postinstall.sh

@@ -0,0 +1,63 @@
+#!/usr/bin/env bash
+# Postinstall script to handle native module prebuilds
+# Bun blocks postinstall scripts by default, so we need to manually trigger them
+set -euo pipefail
+
+# Find node-compatible runtime (prefer node, fallback to bun)
+if command -v node &> /dev/null; then
+  NODE_BIN="node"
+elif command -v bun &> /dev/null; then
+  NODE_BIN="bun"
+elif [ -f "/usr/local/bin/bun" ]; then
+  NODE_BIN="/usr/local/bin/bun"
+elif [ -f "$HOME/.bun/bin/bun" ]; then
+  NODE_BIN="$HOME/.bun/bin/bun"
+else
+  echo "Error: Neither node nor bun found in PATH"
+  exit 1
+fi
+
+# Color output for better visibility
+RED='\033[0;31m'
+GREEN='\033[0;32m'
+YELLOW='\033[1;33m'
+NC='\033[0m' # No Color
+
+echo "Running postinstall tasks..."
+
+# Install node-pty prebuilds
+# The package has an install script that downloads prebuilt binaries from GitHub
+if [ -d "node_modules/@homebridge/node-pty-prebuilt-multiarch" ]; then
+  echo -e "${GREEN}Installing node-pty prebuilds...${NC}"
+  cd node_modules/@homebridge/node-pty-prebuilt-multiarch
+  
+  # Run the install script using prebuild-install (downloads prebuilts from GitHub)
+  # Check if already installed first
+  if [ -f "build/Release/pty.node" ]; then
+    echo -e "${GREEN}✓ node-pty prebuild already exists (build/Release/pty.node)${NC}"
+  else
+    echo -e "${YELLOW}Downloading node-pty prebuilds...${NC}"
+    # Run prebuild-install (may crash with bun, but still downloads the binary)
+    $NODE_BIN ../../prebuild-install/bin.js --verbose > /tmp/node-pty-install.log 2>&1 || true
+    
+    # Check if the binary was actually installed
+    if [ -f "build/Release/pty.node" ]; then
+      echo -e "${GREEN}✓ node-pty prebuilds downloaded successfully${NC}"
+    else
+      echo -e "${YELLOW}⚠ Failed to install node-pty prebuilds${NC}"
+      echo -e "${YELLOW}Terminals may not work in packaged Electron app${NC}"
+      echo -e "${YELLOW}To fix manually, run:${NC}"
+      echo -e "${YELLOW}  cd node_modules/@homebridge/node-pty-prebuilt-multiarch${NC}"
+      echo -e "${YELLOW}  node ../../prebuild-install/bin.js --verbose${NC}"
+      # Don't exit 1 - let the build continue, terminals will just be degraded
+    fi
+  fi
+  
+  cd ../..
+else
+  echo -e "${YELLOW}Warning: @homebridge/node-pty-prebuilt-multiarch not found in node_modules${NC}"
+  echo -e "${YELLOW}Run 'bun install' first${NC}"
+  exit 1
+fi
+
+echo -e "${GREEN}Postinstall completed successfully${NC}"