refactor(ui): modernize status bar and component structure

This commit introduces a comprehensive overhaul of the application's UI, focusing on modernizing the global workspace status bar and improving overall theming consistency. Several components were refactored to simplify prop handling and improve separation of concerns, particularly within the TitleBar and RepoToolbar. The CSS includes extensive new variables and styles for better visual fidelity across light and dark themes.

- Overhauled the main application footer to display version, branch status, and sync metrics.
- Added global CSS variables and component styling for a modern look.
- Simplified repository state management by removing redundant props from TitleBar.

src/lib/TitleBar.svelte

@@ -1,15 +1,9 @@
 <script lang="ts">
   import { onDestroy, onMount } from "svelte";
-  import { getVersion } from "@tauri-apps/api/app";
   import { getCurrentWindow } from "@tauri-apps/api/window";
-  import { CircleHelp, GitBranch, Minus, Settings, X } from "@lucide/svelte";
+  import { CircleHelp, Minus, Settings, X } from "@lucide/svelte";
   import iconUrl from "../../src-tauri/icons/icon.png";
 
-  export let branch: string = "";
-  export let ahead: number = 0;
-  export let behind: number = 0;
-  export let repoName: string = "";
-  export let hasRepository: boolean = false;
   export let onOpenHelp: () => void = () => {};
   export let onOpenSettings: () => void = () => {};
   export let language: "en" | "de" = "en";
@@ -17,7 +11,6 @@
   let win: ReturnType<typeof getCurrentWindow> | null = null;
   let isMaximized = false;
   let unlisten: (() => void) | undefined;
-  let appVersion = "";
 
   onMount(async () => {
     try {
@@ -29,12 +22,6 @@
     } catch {
       win = null;
     }
-
-    try {
-      appVersion = await getVersion();
-    } catch {
-      appVersion = "";
-    }
   });
 
   onDestroy(() => {
@@ -61,36 +48,9 @@
       <img src={iconUrl} alt="" data-tauri-drag-region />
     </span>
     <span data-tauri-drag-region>Gitty</span>
-    {#if appVersion}
-      <span class="tb-version" data-tauri-drag-region title="Version {appVersion}">v{appVersion}</span>
-    {/if}
   </div>
 
-  <!-- Center: repo + branch info -->
-  <div class="titlebar-info" data-tauri-drag-region>
-    {#if hasRepository}
-      <div class="titlebar-context" data-tauri-drag-region>
-        {#if repoName}
-          <span class="tb-repo" data-tauri-drag-region>{repoName}</span>
-          <span class="tb-sep" data-tauri-drag-region aria-hidden="true">/</span>
-        {/if}
-        <GitBranch size={12} aria-hidden="true" />
-        <span class="tb-branch" data-tauri-drag-region title={branch}>{branch}</span>
-      </div>
-      {#if ahead > 0 || behind > 0}
-        <div class="tb-sync-group" aria-label="Branch synchronization status">
-          {#if ahead > 0}
-            <span class="tb-sync ahead" title="{ahead} commits ahead">↑{ahead}</span>
-          {/if}
-          {#if behind > 0}
-            <span class="tb-sync behind" title="{behind} commits behind">↓{behind}</span>
-          {/if}
-        </div>
-      {/if}
-    {:else}
-      <span class="tb-no-repo" data-tauri-drag-region>No repository open</span>
-    {/if}
-  </div>
+  <div class="titlebar-drag" data-tauri-drag-region aria-hidden="true"></div>
 
   <!-- Right: app-global actions + window controls -->
   <div class="titlebar-globals">