Add dev live-reload tooling

DevPlugin (native + TS) lets the running app switch its webview to a
Vite dev server via DEV_URL, toggled from a hidden DevMenu (5 taps on
the app title).

client/android/app/src/main/java/com/tiptoisync/app/MainActivity.kt

@@ -3,10 +3,26 @@ package com.tiptoisync.app
 import android.os.Bundle
 import androidx.core.view.WindowCompat
 import com.getcapacitor.BridgeActivity
+import com.getcapacitor.CapConfig
 
 class MainActivity : BridgeActivity() {
     override fun onCreate(savedInstanceState: Bundle?) {
+        // Dev-URL aus SharedPreferences lesen, bevor die Bridge initialisiert wird.
+        // "CapacitorStorage" ist der von @capacitor/preferences genutzte SharedPreferences-Name.
+        val devUrl = getSharedPreferences("CapacitorStorage", MODE_PRIVATE)
+            .getString("devServerUrl", null)
+
+        if (devUrl != null) {
+            // CapConfig mit der Dev-Server-URL überschreiben – die Bridge lädt dann
+            // direkt vom Vite Dev-Server und injiziert die Bridge trotzdem korrekt.
+            config = CapConfig.Builder(this)
+                .setServerUrl(devUrl)
+                .setAllowMixedContent(true)
+                .create()
+        }
+
         registerPlugin(TiptoiPlugin::class.java)
+        registerPlugin(DevPlugin::class.java)
         super.onCreate(savedInstanceState)
         WindowCompat.setDecorFitsSystemWindows(window, false)
     }

client/src/components/DevMenu.tsx

@@ -0,0 +1,81 @@
+import { createSignal, onMount, Show } from 'solid-js'
+import { Preferences } from '@capacitor/preferences'
+import { Dev } from '../native/DevPlugin'
+
+const DEV_URL_KEY = 'devServerUrl'
+
+interface Props {
+  onClose: () => void
+}
+
+export default function DevMenu(props: Props) {
+  const [url, setUrl] = createSignal('')
+  const [saved, setSaved] = createSignal<string | null>(null)
+
+  onMount(async () => {
+    const { value } = await Preferences.get({ key: DEV_URL_KEY })
+    setSaved(value)
+    setUrl(value ?? '')
+  })
+
+  const handleSave = async () => {
+    const trimmed = url().trim()
+    if (!trimmed) return
+    // Speichern + Activity-Neustart → Bridge initialisiert sich mit Dev-URL
+    await Dev.activate({ url: trimmed })
+  }
+
+  const handleClear = async () => {
+    // Entfernen + Activity-Neustart → Bridge initialisiert sich mit gebundelter App
+    await Dev.deactivate()
+  }
+
+  return (
+    <div class="dev-menu-backdrop" onClick={props.onClose}>
+      <div class="dev-menu" onClick={e => e.stopPropagation()}>
+        <div class="dev-menu__header">
+          <span class="dev-menu__title">⚙️ Dev-Modus</span>
+          <button class="dev-menu__close" onClick={props.onClose}>✕</button>
+        </div>
+
+        <p class="dev-menu__desc">
+          Vite Dev-Server URL eintragen. Die App lädt dann JavaScript direkt
+          vom Dev-Server – inkl. Hot Reload. Native Plugins bleiben aktiv.
+        </p>
+
+        <Show when={saved()}>
+          <div class="dev-menu__active">
+            <span class="dev-menu__active-dot" />
+            Aktiv: <code>{saved()}</code>
+          </div>
+        </Show>
+
+        <div class="dev-menu__row">
+          <input
+            class="input"
+            type="url"
+            placeholder="http://192.168.1.42:5173"
+            value={url()}
+            onInput={e => setUrl(e.currentTarget.value)}
+            onKeyDown={e => e.key === 'Enter' && handleSave()}
+          />
+        </div>
+
+        <div class="dev-menu__actions">
+          <button
+            class="btn"
+            onClick={handleSave}
+            disabled={!url().trim() || url().trim() === saved()}
+          >
+            Speichern &amp; verbinden
+          </button>
+          <Show when={saved()}>
+            <button class="btn btn--ghost" onClick={handleClear}>
+              Dev-Modus deaktivieren
+            </button>
+          </Show>
+        </div>
+      </div>
+    </div>
+  )
+}

client/src/native/DevPlugin.ts

@@ -0,0 +1,8 @@
+import { registerPlugin } from '@capacitor/core'
+
+export interface DevPlugin {
+  activate(options: { url: string }): Promise<void>
+  deactivate(): Promise<void>
+}
+
+export const Dev = registerPlugin<DevPlugin>('Dev')