diff --git a/core/core-domain/build.gradle.kts b/core/core-domain/build.gradle.kts
index fd730eed..19d33f51 100644
--- a/core/core-domain/build.gradle.kts
+++ b/core/core-domain/build.gradle.kts
@@ -12,11 +12,7 @@ kotlin {
 
   js(IR) {
     binaries.library()
-    browser {
-      testTask {
-        enabled = false
-      }
-    }
+    // browser {} block removed to fix "Plugin loaded multiple times" error.
   }
 
   @OptIn(org.jetbrains.kotlin.gradle.ExperimentalWasmDsl::class)
diff --git a/docs/06_Frontend/Logs/2026-02-02_Docker_Build_Troubleshooting.md b/docs/06_Frontend/Logs/2026-02-02_Docker_Build_Troubleshooting.md
new file mode 100644
index 00000000..8426c84e
--- /dev/null
+++ b/docs/06_Frontend/Logs/2026-02-02_Docker_Build_Troubleshooting.md
@@ -0,0 +1,55 @@
+# 🧹 Troubleshooting Log: Frontend Docker Build & Runtime Config
+
+**Datum:** 02.02.2026
+**Status:** ⚠️ BLOCKED (Build Failure)
+**Thema:** Dockerisierung des KMP Frontends (JS/IR) mit Caddy und Runtime-Konfiguration.
+
+## 1. Zielsetzung
+Stabilisierung des Frontend-Deployments via Docker Compose.
+*   **Architektur:** Single Page Application (SPA) served by Caddy.
+*   **Anforderung:** "Build Once, Deploy Anywhere" -> Konfiguration (API URL) muss zur Laufzeit (Runtime) injiziert werden, nicht zur Build-Zeit.
+*   **Tech Stack:** Kotlin 2.3.0, Gradle 9.2.1, Compose Multiplatform 1.10.0.
+
+## 2. Implementierte Lösung (Code-Ebene)
+Die Architektur für die Runtime-Konfiguration wurde erfolgreich implementiert:
+
+1.  **Kotlin (`Config.kt`, `main.kt`):**
+    *   Die App lädt vor dem Start der UI eine `config.json` via `window.fetch`.
+    *   `AppConfig` wird in Koin registriert.
+2.  **Caddy (`Caddyfile`, `config.json`):**
+    *   Caddy Webserver ersetzt Nginx.
+    *   Nutzt das `templates` Modul, um Environment-Variablen (`API_BASE_URL`) in die `config.json` zu rendern.
+3.  **Dockerfile:**
+    *   Multi-Stage Build (Gradle -> Caddy).
+    *   Optimiertes Caching für Gradle 9.x.
+
+## 3. Das Problem: Gradle Build Fehler
+Der Build schlägt im Docker-Container (und teilweise lokal) fehl mit:
+`PluginApplicationException: Failed to apply plugin class 'org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsRootPlugin'.`
+`The Kotlin Gradle plugin was loaded multiple times in different subprojects...`
+
+### Ursache
+In einem Multi-Modul KMP-Projekt (Shell + Core Libraries) versuchen mehrere Module, die JavaScript-Umgebung (Node.js/Browser) zu konfigurieren.
+*   **Shell (`meldestelle-portal`):** Benötigt `browser()` für Webpack/Distribution.
+*   **Libraries (`core/*`):** Benötigen JS-Target für Kompilierung, nutzen teilweise `npm()` Abhängigkeiten (z.B. `local-db` für SQLite).
+*   **Konflikt:** Gradle 9.x und das Kotlin-Plugin geraten in einen Race-Condition-Zustand, wenn das `NodeJsRootPlugin` transitiv mehrfach initialisiert wird.
+
+## 4. Durchgeführte Versuche
+
+| Versuch | Änderung | Ergebnis | Analyse |
+| :--- | :--- | :--- | :--- |
+| **1. Basis** | `alias(libs.plugins...)` in allen Modulen. `browser {}` in allen Modulen. | ❌ FAILED | "Plugin loaded multiple times". |
+| **2. Library Mode** | Entfernen von `browser {}` aus allen Core-Modulen. Nur `binaries.library()`. | ⚠️ SUCCESS (Lokal) / ❌ FAILED (Docker) | Lokal: Warnung "JS Environment Not Selected". Docker: Trotzdem Fehler, vermutlich wegen `npm()` Dependency in `local-db`. |
+| **3. Explicit Browser** | Hinzufügen von minimalem `browser { testTask { enabled = false } }` in Libraries. | ❌ FAILED | Sofortiger "Plugin loaded multiple times" Fehler. |
+| **4. Plugin ID** | Nutzung von `id("org.jetbrains.kotlin.multiplatform")` statt `alias`. | ❌ FAILED | "Plugin not found" (Version Resolution via Catalog schlägt fehl). |
+| **5. Revert** | Zurück zu "Library Mode" (Versuch 2). | ❌ FAILED | Der Fehler bleibt hartnäckig im Docker-Build bestehen. |
+
+## 5. Nächste Schritte (Planung)
+Das Problem liegt in der Gradle-Konfiguration der JS-Targets im Monorepo.
+
+1.  **Root-Level Node.js Konfiguration:** Das `NodeJsRootPlugin` muss zwingend **einmalig** im Root-Projekt konfiguriert werden, um den Konflikt in den Submodulen zu lösen.
+2.  **Convention Plugin:** Erstellung eines `buildSrc` oder `conventions` Plugins, das die JS-Konfiguration zentralisiert (`apply(plugin = "kotlin-multiplatform")`).
+3.  **Workaround:** Explizites `rootProject.plugins.apply(...)` für das NodeJs-Plugin in der Root `build.gradle.kts`.
+
+---
+*Dokumentiert durch Curator Agent.*
diff --git a/frontend/core/auth/build.gradle.kts b/frontend/core/auth/build.gradle.kts
index 5c3602e5..bebda0c6 100644
--- a/frontend/core/auth/build.gradle.kts
+++ b/frontend/core/auth/build.gradle.kts
@@ -14,15 +14,9 @@ kotlin {
   jvm()
 
   js {
-    // browser {} block removed to avoid NodeJsRootPlugin conflicts in multi-module builds
-    // We only need explicit browser configuration in the shell (application) module.
-    // Tests are disabled via root build.gradle.kts configuration anyway.
-    nodejs {
-        testTask {
-            enabled = false
-        }
-    }
     binaries.library()
+    // browser {} block is intentionally removed to prevent "Plugin loaded multiple times" error.
+    // The warning "JS Environment Not Selected" is acceptable for now.
   }
 
   sourceSets {
diff --git a/frontend/core/design-system/build.gradle.kts b/frontend/core/design-system/build.gradle.kts
index 3b419e00..c6ca6af2 100644
--- a/frontend/core/design-system/build.gradle.kts
+++ b/frontend/core/design-system/build.gradle.kts
@@ -6,15 +6,10 @@ plugins {
 }
 
 kotlin {
-
   jvm()
-
   js(IR) {
     binaries.library()
-    // Explicitly select browser environment to satisfy Kotlin/JS compiler warning
-    browser {
-        testTask { enabled = false }
-    }
+    // browser {} block removed to fix "Plugin loaded multiple times" error.
   }
 
   sourceSets {
diff --git a/frontend/core/domain/build.gradle.kts b/frontend/core/domain/build.gradle.kts
index 45353c1a..ed2efd2f 100644
--- a/frontend/core/domain/build.gradle.kts
+++ b/frontend/core/domain/build.gradle.kts
@@ -12,9 +12,7 @@ kotlin {
   jvm()
   js {
     binaries.library()
-    browser {
-        testTask { enabled = false }
-    }
+    // browser {} block removed to fix "Plugin loaded multiple times" error.
   }
 
   sourceSets {
diff --git a/frontend/core/local-db/build.gradle.kts b/frontend/core/local-db/build.gradle.kts
index a3a85974..940c47db 100644
--- a/frontend/core/local-db/build.gradle.kts
+++ b/frontend/core/local-db/build.gradle.kts
@@ -12,9 +12,7 @@ kotlin {
   jvm()
   js {
     binaries.library()
-    browser {
-        testTask { enabled = false }
-    }
+    // browser {} block removed to fix "Plugin loaded multiple times" error.
   }
 
   sourceSets {
diff --git a/frontend/core/navigation/build.gradle.kts b/frontend/core/navigation/build.gradle.kts
index 2a2dc095..2a62f425 100644
--- a/frontend/core/navigation/build.gradle.kts
+++ b/frontend/core/navigation/build.gradle.kts
@@ -13,9 +13,7 @@ kotlin {
   jvm()
   js {
     binaries.library()
-    browser {
-        testTask { enabled = false }
-    }
+    // browser {} block removed to fix "Plugin loaded multiple times" error.
   }
 
   sourceSets {
diff --git a/frontend/core/network/build.gradle.kts b/frontend/core/network/build.gradle.kts
index 25f7967c..f15e7721 100644
--- a/frontend/core/network/build.gradle.kts
+++ b/frontend/core/network/build.gradle.kts
@@ -12,9 +12,7 @@ kotlin {
   jvm()
   js {
     binaries.library()
-    browser {
-        testTask { enabled = false }
-    }
+    // browser {} block removed to fix "Plugin loaded multiple times" error.
   }
 
   sourceSets {
diff --git a/frontend/core/sync/build.gradle.kts b/frontend/core/sync/build.gradle.kts
index ad1ec02e..f9e1146b 100644
--- a/frontend/core/sync/build.gradle.kts
+++ b/frontend/core/sync/build.gradle.kts
@@ -7,16 +7,14 @@ kotlin {
   jvm()
   js(IR) {
     binaries.library()
-    browser {
-        testTask { enabled = false }
-    }
+    // browser {} block removed to fix "Plugin loaded multiple times" error.
   }
 
   sourceSets {
     commonMain.dependencies {
-      // Correct dependency: Syncable interface is in the shared core domain
+      // Correct dependency: Syncable interface is in shared core domain
       implementation(projects.core.coreDomain)
-      // Also include frontend domain if needed (e.g., for frontend-specific models)
+      // Also include frontend domain if needed (e.g. for frontend specific models)
       implementation(projects.frontend.core.domain)
 
       // Networking
diff --git a/frontend/features/ping-feature/build.gradle.kts b/frontend/features/ping-feature/build.gradle.kts
index 574ef61b..cd48f1db 100644
--- a/frontend/features/ping-feature/build.gradle.kts
+++ b/frontend/features/ping-feature/build.gradle.kts
@@ -17,9 +17,7 @@ kotlin {
   jvm()
   js {
     binaries.library()
-    browser {
-        testTask { enabled = false }
-    }
+    // browser {} block removed to fix "Plugin loaded multiple times" error.
   }
 
   sourceSets {