feat(canvas): Replace emoji icons with professional Lucide React icons

Phase 1 of Canvas Professional Upgrade:
- Replace all emoji icons in nodes with Lucide components
- Update BaseNode to use iconColor prop instead of color/colorBg
- Update NodePalette with matching Lucide icons
- Update templates.ts with Lucide icon names (Box, Scale, BarChart3, etc.)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

atomizer-dashboard/frontend/src/lib/canvas/templates.ts

@@ -24,7 +24,7 @@ const massMinimizationTemplate: CanvasTemplate = {
   name: 'Mass Minimization',
   description: 'Minimize structural mass while maintaining stiffness constraints. Ideal for brackets, housings, and weight-critical components.',
   category: 'structural',
-  icon: '⚖️',
+  icon: 'Scale',
   intent: {
     version: '1.0',
     source: 'canvas',
@@ -67,7 +67,7 @@ const multiObjectiveTemplate: CanvasTemplate = {
   name: 'Multi-Objective Pareto',
   description: 'Explore trade-offs between competing objectives. Generates a Pareto front for informed decision-making.',
   category: 'structural',
-  icon: '📊',
+  icon: 'BarChart3',
   intent: {
     version: '1.0',
     source: 'canvas',
@@ -112,7 +112,7 @@ const turboModeTemplate: CanvasTemplate = {
   name: 'Turbo Mode',
   description: 'Accelerated optimization using neural network surrogates. Run thousands of virtual trials with periodic FEA validation.',
   category: 'general',
-  icon: '🚀',
+  icon: 'Rocket',
   intent: {
     version: '1.0',
     source: 'canvas',
@@ -158,7 +158,7 @@ const mirrorZernikeTemplate: CanvasTemplate = {
   name: 'Mirror Zernike',
   description: 'Optimize optical mirror surface quality using Zernike wavefront error metrics. Specialized for precision optics.',
   category: 'optical',
-  icon: '🔭',
+  icon: 'Telescope',
   intent: {
     version: '1.0',
     source: 'canvas',
@@ -208,7 +208,7 @@ const frequencyOptimizationTemplate: CanvasTemplate = {
   name: 'Frequency Optimization',
   description: 'Maximize natural frequencies to avoid resonance. Essential for rotating machinery and vibration-sensitive equipment.',
   category: 'structural',
-  icon: '📈',
+  icon: 'TrendingUp',
   intent: {
     version: '1.0',
     source: 'canvas',