[BUG]: Asset Folder Typo (`assests` -> `assets`)

### Bug Description

The `src/assests` directory is misspelled. The correct spelling should be `src/assets`.

This typo is also reflected in multiple import paths, making the project structure inconsistent and potentially causing confusion when adding or referencing assets.

**Proposed Fix**

Rename:

```text
src/assests/
```

to:

```text
src/assets/
```

and update all references from `assests` to `assets`.

Known affected files:

* `src/components/Navbar.jsx`
* `src/components/layout/Footer.jsx`
* `src/pages/Support.jsx`

### Steps to Reproduce

1. Open the `src` directory.
2. Observe the `assests` directory.
3. Check asset imports in `Navbar.jsx`, `Footer.jsx`, and `Support.jsx`.
4. Notice that they reference the misspelled `assests` path.

### Logs and Screenshots

No runtime error is required to reproduce this issue. The problem is visible in the directory structure and import paths.

### Environment Details

* OS: Windows / Linux / macOS
* Project: OrgExplorer
* Frontend: React + Vite

### Impact

Low - Minor inconvenience

### Code of Conduct

- [x] I have joined the [Discord server](https://discord.gg/hjUhu33uAn) and will post updates there
- [x] I have searched existing issues to avoid duplicates

Start by locating src/assests and searching the repository for every occurrence of "assests". Inspect the imports in src/components/Navbar.jsx, src/components/layout/Footer.jsx, and src/pages/Support.jsx, then update references alongside the directory rename. Done means the directory is src/assets and no project references use the misspelled path.

索引モデルが issue の本文から書いたものです。