feat: add runtime configuration for Caddy-based SPA containerization

Introduced `config.json` runtime configuration fetch mechanism to support the "Build Once, Deploy Everywhere" pattern. Replaced NGINX with Caddy for SPA deployment, enabling SPA routing, security headers, and static asset management. Updated Gradle and Kotlin/JS build configurations to align with the new runtime environment. Enhanced Dockerfile and health checks for optimized CI/CD workflows and improved SPA delivery.

frontend/core/navigation/build.gradle.kts

@@ -10,28 +10,14 @@ group = "at.mocode.clients.shared"
 version = "1.0.0"
 
 kotlin {
-  // Toolchain is now handled centrally in the root build.gradle.kts
-
   jvm()
-
   js {
+    binaries.library()
     browser {
-      testTask {
-        // Browser testing is disabled to avoid environment issues (e.g. missing ChromeHeadless).
-        // Tests are still run on JVM.
-        enabled = false
-      }
+        testTask { enabled = false }
     }
   }
 
-  // Wasm vorerst deaktiviert
-  /*
-  @OptIn(org.jetbrains.kotlin.gradle.ExperimentalWasmDsl::class)
-  wasmJs {
-    browser()
-  }
-  */
-
   sourceSets {
     commonMain.dependencies {
       // Depend on core domain for User/Role types used by navigation API