Closes #ISSUE-009 - Implement DEV_MODE Offline-First Protection Shield

app/api/tech/ai/route.ts

@@ -134,9 +134,10 @@ async function fetchFmpData(ticker: string, apiKey: string): Promise<any> {
 export async function GET() {
   const apiKey = process.env.FMP_API_KEY;
   const now = Date.now();
+  const isDevMode = process.env.DEV_MODE === 'true';
 
-  // Return cached result if valid
-  if (cache && (now - cache.timestamp < CACHE_TTL)) {
+  // Return cached result if valid (unless in DEV_MODE)
+  if (!isDevMode && cache && (now - cache.timestamp < CACHE_TTL)) {
     return NextResponse.json(cache.data, {
       status: 200,
       headers: { 'Cache-Control': 'public, max-age=3600' }
@@ -147,7 +148,9 @@ export async function GET() {
   // Deep clone fallback data
   const companyData: CompanyData[] = JSON.parse(JSON.stringify(MOCK_TECH_AI_DATA));
 
-  if (apiKey) {
+  if (isDevMode) {
+    // Short-circuit: completely skip outbound FMP fetches
+  } else if (apiKey) {
     try {
       // Test the API key first with a quick check
       const testRes = await fetchWithTimeout(`https://financialmodelingprep.com/api/v3/income-statement/NVDA?period=quarter&limit=1&apikey=${apiKey}`);
@@ -422,6 +425,7 @@ export async function GET() {
   const payload = {
     dates,
     liveDataAvailable,
+    isShieldActive: isDevMode,
     timestamp: now,
     metrics: {
       monetizationGap: {
@@ -436,13 +440,22 @@ export async function GET() {
     }
   };
 
-  cache = {
-    timestamp: now,
-    data: payload
+  if (!isDevMode) {
+    cache = {
+      timestamp: now,
+      data: payload
+    };
+  }
+
+  const responseHeaders: Record<string, string> = {
+    'Cache-Control': isDevMode ? 'no-store, max-age=0, must-revalidate' : 'public, max-age=3600'
   };
+  if (isDevMode) {
+    responseHeaders['X-Shield-Active'] = 'true';
+  }
 
   return NextResponse.json(payload, {
     status: 200,
-    headers: { 'Cache-Control': 'public, max-age=3600' }
+    headers: responseHeaders
   });
 }