refactor: refactor smart entry as standalone modal overlay

- Convert TravelReimbursementCreateView from page to modal overlay
- Simplify App.vue navigation flow with smartEntryOpen state
- Add create-request button in RequestsView

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/components/layout/TopBar.vue

@@ -92,7 +92,7 @@
           </div>
         </div>
         <div class="topbar-spacer"></div>
-        <button class="create-top-btn" type="button">
+        <button class="create-top-btn" type="button" @click="emit('newApplication')">
           <i class="mdi mdi-plus"></i>
           <span>发起报销</span>
         </button>