feat: configurable bottom navigation bar (Issue #23)

## What
Adds a new Navigation Bar section to Settings where users can customize which items appear in the bottom navigation bar.

## Features
- Pick from any of the 19 drawer screens (max 5 items)
- Remove items with a close/delete button
- Items persist via SharedPreferences (CSV format)
- Invalid names are silently dropped
- Existing screens and auth-aware filtering respected

Closes #23

README.md

@@ -295,11 +295,3 @@ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 ```
-
----
-
-<p align="center">
-  Built with ❤️ by <a href="https://github.com/Hy4ri">Hy4ri</a>
-  <br>
-  <sub>Hermes Agent by <a href="https://nousresearch.com">Nous Research</a></sub>
-</p>