miden new template: integration/Cargo.toml missing miden-protocol dependency

The docs Get Started guide has SDK examples on the Notes & Transactions page (mint / consume / send) that import `miden_protocol`:

```rust
use miden_protocol::asset::{AssetAmount, FungibleAsset, TokenSymbol};
```

If you scaffold a project with `cargo miden new` and paste that example in, it fails to build, because the generated `integration/Cargo.toml` doesn't depend on `miden-protocol` (it has miden-client, miden-client-sqlite-store, miden-standards, miden-testing, miden-mast-package):

```
error[E0433]: cannot find module or crate `miden_protocol`
--> integration/src/bin/mint.rs:18:5
|
18 | use miden_protocol::asset::{AssetAmount, FungibleAsset, TokenSymbol};
| ^^^^^^^^^^^^^^ use of unresolved module or unlinked crate `miden_protocol`
```

Two fixes:
1. Add `miden-protocol` (0.15) to this template's `integration/Cargo.toml`.
2. Fix the docs example (tracked in the docs issue: 0xMiden/docs#343).

Full report: https://github.com/0xMiden/feedback/issues/149.