refactor: make 'generatedAt' optional in component metadata and remove timestamp generation to prevent CI drift

frontend/public/components-metadata.json

@@ -1,6 +1,5 @@
 {
   "version": "1.0.0",
-  "generatedAt": "2026-04-21T18:09:56.254Z",
   "components": [
     {
       "thumbnail": "<svg width=\"64\" height=\"64\" xmlns=\"http://www.w3.org/2000/svg\">\n      <rect width=\"64\" height=\"64\" fill=\"#e0e0e0\" rx=\"4\"/>\n      <text x=\"50%\" y=\"50%\" text-anchor=\"middle\" dy=\".3em\" font-size=\"10\" fill=\"#666\">\n        DIODE-1N4007\n      </text>\n    </svg>",

frontend/src/types/component-metadata.ts

@@ -45,6 +45,6 @@ export interface ComponentMetadata {
 
 export interface ComponentMetadataCollection {
   version: string;
-  generatedAt: string;
+  generatedAt?: string;
   components: ComponentMetadata[];
 }

scripts/generate-component-metadata.ts

@@ -144,9 +144,10 @@ class MetadataGenerator {
       return a.name.localeCompare(b.name);
     });
 
+    // Note: no `generatedAt` timestamp — it would change on every run and
+    // break the CI drift check (git diff --quiet on the committed JSON).
     const output = {
       version: '1.0.0',
-      generatedAt: new Date().toISOString(),
       components,
     };