fix(brand): unified blue color system across all dashboard tabs

- StyleInsights: green/purple stats → blue-500
- StyleInsights: green percentage badges → blue variant
- DependencyGraph: mixed white/green/blue stats → all blue-500
- ImpactAnalyzer: yellow/green stats → blue-500
- Preserved semantic colors for risk indicators (red/yellow/green)

Brand rule: ALL stat numbers use blue-500, semantic colors only for risk

Author: DevanshuNEU

frontend/src/components/DependencyGraph.tsx

@@ -235,21 +235,21 @@ export function DependencyGraph({ repoId, apiUrl, apiKey }: DependencyGraphProps
       <div className="grid grid-cols-1 md:grid-cols-4 gap-4">
         <div className="bg-[#0a0a0c] border border-white/5 rounded-xl p-5">
           <div className="text-sm text-gray-400 mb-1">Total Files</div>
-          <div className="text-3xl font-bold text-white">{allNodes.length}</div>
+          <div className="text-3xl font-bold text-blue-500">{allNodes.length}</div>
         </div>
         <div className="bg-[#0a0a0c] border border-white/5 rounded-xl p-5">
           <div className="text-sm text-gray-400 mb-1">Dependencies</div>
-          <div className="text-3xl font-bold text-blue-400">{edges.length}</div>
+          <div className="text-3xl font-bold text-blue-500">{edges.length}</div>
         </div>
         <div className="bg-[#0a0a0c] border border-white/5 rounded-xl p-5">
           <div className="text-sm text-gray-400 mb-1">Avg per File</div>
-          <div className="text-3xl font-bold text-white">
+          <div className="text-3xl font-bold text-blue-500">
             {metrics?.avg_dependencies?.toFixed(1) || 0}
           </div>
         </div>
         <div className="bg-[#0a0a0c] border border-white/5 rounded-xl p-5">
           <div className="text-sm text-gray-400 mb-1">Showing</div>
-          <div className="text-3xl font-bold text-green-400">{nodes.length}</div>
+          <div className="text-3xl font-bold text-blue-500">{nodes.length}</div>
         </div>
       </div>
 

frontend/src/components/ImpactAnalyzer.tsx

@@ -129,7 +129,7 @@ export function ImpactAnalyzer({ repoId, apiUrl, apiKey }: ImpactAnalyzerProps)
           <div className="grid grid-cols-1 md:grid-cols-3 gap-4">
             <div className="bg-[#0a0a0c] border border-white/5 rounded-xl p-5">
               <div className="text-sm text-gray-400 mb-1">Direct Dependencies</div>
-              <div className="text-3xl font-bold text-blue-400">
+              <div className="text-3xl font-bold text-blue-500">
                 {result.dependency_count}
               </div>
               <div className="text-xs text-gray-500 mt-1">
@@ -139,7 +139,7 @@ export function ImpactAnalyzer({ repoId, apiUrl, apiKey }: ImpactAnalyzerProps)
 
             <div className="bg-[#0a0a0c] border border-white/5 rounded-xl p-5">
               <div className="text-sm text-gray-400 mb-1">Total Impact</div>
-              <div className="text-3xl font-bold text-yellow-400">
+              <div className="text-3xl font-bold text-blue-500">
                 {result.dependent_count}
               </div>
               <div className="text-xs text-gray-500 mt-1">
@@ -149,7 +149,7 @@ export function ImpactAnalyzer({ repoId, apiUrl, apiKey }: ImpactAnalyzerProps)
 
             <div className="bg-[#0a0a0c] border border-white/5 rounded-xl p-5">
               <div className="text-sm text-gray-400 mb-1">Test Files</div>
-              <div className="text-3xl font-bold text-green-400">
+              <div className="text-3xl font-bold text-blue-500">
                 {result.test_files?.length || 0}
               </div>
               <div className="text-xs text-gray-500 mt-1">

frontend/src/components/StyleInsights.tsx

@@ -41,14 +41,14 @@ export function StyleInsights({ repoId, apiUrl, apiKey }: StyleInsightsProps) {
 
         <div className="bg-[#0a0a0c] border border-white/5 rounded-xl p-5">
           <div className="text-sm text-gray-400 mb-1">Async Adoption</div>
-          <div className="text-3xl font-bold text-green-400">
+          <div className="text-3xl font-bold text-blue-500">
             {data.summary?.async_adoption || '0%'}
           </div>
         </div>
 
         <div className="bg-[#0a0a0c] border border-white/5 rounded-xl p-5">
           <div className="text-sm text-gray-400 mb-1">Type Hints</div>
-          <div className="text-3xl font-bold text-purple-400">
+          <div className="text-3xl font-bold text-blue-500">
             {data.summary?.type_hints_usage || '0%'}
           </div>
         </div>
@@ -126,7 +126,7 @@ export function StyleInsights({ repoId, apiUrl, apiKey }: StyleInsightsProps) {
             <span className="text-gray-300">Async/Await Usage</span>
             <div className="flex items-center gap-2">
               <span className="text-gray-500">{data.patterns?.async_usage}</span>
-              <span className="px-2 py-0.5 text-xs bg-green-500/10 text-green-400 border border-green-500/20 rounded">
+              <span className="px-2 py-0.5 text-xs bg-blue-500/10 text-blue-400 border border-blue-500/20 rounded">
                 {data.patterns?.async_percentage?.toFixed(0)}%
               </span>
             </div>
@@ -136,7 +136,7 @@ export function StyleInsights({ repoId, apiUrl, apiKey }: StyleInsightsProps) {
             <span className="text-gray-300">Type Annotations</span>
             <div className="flex items-center gap-2">
               <span className="text-gray-500">{data.patterns?.type_annotations}</span>
-              <span className="px-2 py-0.5 text-xs bg-green-500/10 text-green-400 border border-green-500/20 rounded">
+              <span className="px-2 py-0.5 text-xs bg-blue-500/10 text-blue-400 border border-blue-500/20 rounded">
                 {data.patterns?.typed_percentage?.toFixed(0)}%
               </span>
             </div>