fix(frontend): add favicon and update references

- Create favicon.svg with blue "S" logo matching app branding
- Update index.html to reference favicon.svg instead of favicon.ico
- Add favicon.svg to angular.json assets configuration

Fixes DEF-004: Browser was showing 404 error for missing favicon.ico
in the console.

src/frontend/angular.json

@@ -26,7 +26,8 @@
             "tsConfig": "tsconfig.app.json",
             "inlineStyleLanguage": "scss",
             "assets": [
-              { "glob": "**/*", "input": "src/assets", "output": "/assets" }
+              { "glob": "**/*", "input": "src/assets", "output": "/assets" },
+              "src/favicon.svg"
             ],
             "styles": [
               "@angular/material/prebuilt-themes/indigo-pink.css",
@@ -71,7 +72,8 @@
             "tsConfig": "tsconfig.spec.json",
             "inlineStyleLanguage": "scss",
             "assets": [
-              { "glob": "**/*", "input": "src/assets", "output": "/assets" }
+              { "glob": "**/*", "input": "src/assets", "output": "/assets" },
+              "src/favicon.svg"
             ],
             "styles": ["src/styles/main.scss"],
             "scripts": []

src/frontend/src/favicon.svg

@@ -0,0 +1,4 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 32 32">
+  <rect width="32" height="32" rx="6" fill="#2563EB"/>
+  <text x="16" y="23" text-anchor="middle" font-family="Inter, system-ui, sans-serif" font-size="18" font-weight="600" fill="white">S</text>
+</svg>

src/frontend/src/index.html

@@ -6,7 +6,7 @@
   <base href="/">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="description" content="Sistema de Registro de Estudiantes - Inter Rapidísimo">
-  <link rel="icon" type="image/x-icon" href="favicon.ico">
+  <link rel="icon" type="image/svg+xml" href="favicon.svg">
   <link href="https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&display=swap" rel="stylesheet">
   <link href="https://fonts.googleapis.com/icon?family=Material+Icons" rel="stylesheet">
 </head>