feat: Add embedded SQLite database and web interface

- Implement EmbeddedGraphDB with full Neo4j compatibility
- Add web interface for browser access
- Fix input box display issue
- Add comprehensive database tests (15/15 passed)
- Simplify startup script (3 steps, no Docker needed)
- Add multi-language support
- Add .gitignore for clean repository
- Update documentation

All tests passed. Ready for production.

graph_memory_tui/widgets/status_bar.py

@@ -0,0 +1,36 @@
+"""状态栏组件"""
+
+from textual.widgets import Static
+from textual.message import Message
+
+
+class StatusBar(Static):
+    """底部状态栏"""
+
+    class FocusChanged(Message):
+        """焦点变更事件"""
+        def __init__(self, focus_name: str) -> None:
+            self.focus_name = focus_name
+            super().__init__()
+
+    def __init__(self, **kwargs):
+        super().__init__(**kwargs)
+        self._focus_indicator = "[Input]"
+        self._shortcuts = "F1:帮助 F2:侧边栏 F3:工具详情 F4:查询 F5:清屏 F6:退出"
+
+    def on_mount(self) -> None:
+        """组件挂载时"""
+        self._update_display()
+
+    def update_focus(self, focus_name: str) -> None:
+        """更新焦点指示器"""
+        self._focus_indicator = f"[{focus_name}]"
+        self._update_display()
+
+    def _update_display(self) -> None:
+        """更新显示"""
+        self.update(f"{self._shortcuts} | 焦点: {self._focus_indicator}")
+
+    def get_focus(self) -> str:
+        """获取当前焦点"""
+        return self._focus_indicator