Add bulk price editing features and fix quantity update price preservation

- Fix FilamentForm to preserve prices when updating quantities
  - Add isInitialLoad flag to prevent price override on form load
  - Only update prices when color is actively changed, not on initial render

- Add bulk filament price editor to dashboard
  - Filter by material and finish
  - Set refill and/or spool prices for multiple filaments
  - Preview changes before applying
  - Update all filtered filaments at once

- Add bulk color price editor to colors page
  - Edit prices for all colors in one interface
  - Global price application with search filtering
  - Individual price editing with change tracking

- Add auto-kill script for dev server
  - Kill existing processes on ports 3000/3001 before starting
  - Prevent "port already in use" errors
  - Clean start every time npm run dev is executed

scripts/kill-dev.sh

@@ -0,0 +1,26 @@
+#!/bin/bash
+
+# Kill any processes running on ports 3000 and 3001
+echo "🔍 Checking for processes on ports 3000 and 3001..."
+PIDS=$(lsof -ti:3000,3001 2>/dev/null)
+if [ -n "$PIDS" ]; then
+  echo "$PIDS" | xargs kill -9 2>/dev/null
+  echo "✅ Killed processes on ports 3000/3001"
+else
+  echo "ℹ️  No processes found on ports 3000/3001"
+fi
+
+# Kill any old Next.js dev server processes (but not the current script)
+echo "🔍 Checking for Next.js dev processes..."
+OLD_PIDS=$(ps aux | grep -i "next dev" | grep -v grep | grep -v "kill-dev.sh" | awk '{print $2}')
+if [ -n "$OLD_PIDS" ]; then
+  echo "$OLD_PIDS" | xargs kill -9 2>/dev/null
+  echo "✅ Killed Next.js dev processes"
+else
+  echo "ℹ️  No Next.js dev processes found"
+fi
+
+# Give it a moment to clean up
+sleep 0.5
+
+echo "✨ Ready to start fresh dev server!"