Note script examples fail to load from removed 0xPolygonMiden/miden-base raw URLs

### Summary

The note script example dropdown fetches examples from the old `0xPolygonMiden/miden-base` raw GitHub path. Those URLs now return 404, so selecting a note script example leaves the editor without the requested example content.

### Code path

`src/utils/helper_functions.tsx` currently fetches:

```ts
https://raw.githubusercontent.com/0xPolygonMiden/miden-base/main/miden-lib/asm/note_scripts/${item}
```

The dropdown options in `src/components/DropDown.tsx` are:

```ts
["P2ID.masm", "P2IDR.masm", "SWAP.masm"]
```

### Verification

The old raw URL for `P2ID.masm` returns 404. The current scripts live under the protocol repository, for example:

- `https://raw.githubusercontent.com/0xMiden/protocol/main/crates/miden-standards/asm/standards/notes/p2id.masm`
- `https://raw.githubusercontent.com/0xMiden/protocol/main/crates/miden-standards/asm/standards/notes/p2ide.masm`
- `https://raw.githubusercontent.com/0xMiden/protocol/main/crates/miden-standards/asm/standards/notes/swap.masm`

### Expected behavior

The dropdown should fetch the note script examples from their current `0xMiden/protocol` location, including the current lowercase filenames and the `P2IDR` to `p2ide.masm` rename.

The issue is in src/utils/helper_functions.tsx where the fetch URL is built. Check the DropDown.tsx component for the list of script names. Update the URL to point to the new base path in the 0xMiden/protocol repository and map the old filenames (P2IDR.masm) to the new lowercase ones (p2ide.masm). Test by selecting an example from the dropdown in the UI and verifying the correct script loads.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.