feat: update ledger instructions (tari-project#6406)

Description
---
- Updated ledger instructions to build natively or via docker.
- Fixed compile errors.

Motivation and Context
---
See above.

How Has This Been Tested?
---
Performed a native build and install of the ledger app on Windows.

What process can a PR reviewer use to test or verify this change?
---
Physical build and install the ledger app.

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Breaking Changes
---

- [x] None
- [ ] Requires data directory on base node to be deleted
- [ ] Requires hard fork
- [ ] Other - Please specify

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applications/minotari_ledger_wallet/wallet/Cargo.toml

@@ -40,6 +40,7 @@ curve = ["ed25519"]
 flags = "0"
 path = ["44'/535348'"]
 name = "MinoTari Wallet"
+api_level = "1"
 
 [package.metadata.ledger.nanos]
 icon = "key.gif"

applications/minotari_ledger_wallet/wallet/README.md

@@ -1,5 +1,25 @@
 # Instructions
 
+## Setup
+
+Ledger does not build with the standard library, so we need to install `rust-src`. This can be done with:
+```
+rustup component add rust-src --toolchain nightly
+```
+
+For loading a BOLOS application to a Ledger device, Ledger has actually written a command, called
+[Cargo Ledger](https://github.com/LedgerHQ/cargo-ledger). This we need to install with:
+```
+cargo install --git https://github.com/LedgerHQ/cargo-ledger cargo-ledger
+```
+
+As per the [Cargo Ledger setup instructions](https://github.com/LedgerHQ/cargo-ledger#setup) run the following to add
+new build targets for the current rust toolchain:
+
+```
+cargo ledger setup
+```
+
 To control ledger devices we use the ledgerctl library.
 We install the supporting Python libraries from Ledger to control Ledger devices,
 [LedgerCTL](https://github.com/LedgerHQ/ledgerctl). This we do with:
@@ -24,6 +44,41 @@ ledgerctl install-ca <NAME>
 
 ## Building
 
+### Native
+
+Open a terminal in the subfolder `./applications/minotari_ledger_wallet/wallet`
+
+_**Note:** Windows users should start a "x64 Native Tools Command Prompt for VS 2019" to have the build tools available
+and then start a python shell within that terminal to have the Python libraries available._
+
+#### Build `ledger`
+
+This must be run from a Python shell (`pip3 --version` should work).
+
+To build, run
+
+```
+cargo ledger build {TARGET} -- "-Zbuild-std=std,alloc"
+```
+
+where TARGET = nanosplus, nanos, etc.
+
+#### Build and install `ledger`
+
+To build and load, run
+
+```
+cargo ledger build {TARGET} --load -- "-Zbuild-std=std,alloc"
+```
+
+where TARGET = nanosplus, nanos, etc.
+
+**Errors**
+
+If the auto-load does not work, try to do a manual installation.
+
+### Using Docker
+
 Ledger does not easily compile locally and it is easiest  to compile via docker using their provided [ledger-app-builder](https://github.com/LedgerHQ/ledger-app-builder/).
 See their readme for setup.
 Once installed you can build the Tari Wallet for ledger by navigating to `./applications/minotari_ledger_wallet` and running the docker command:
@@ -41,7 +96,7 @@ cargo ledger build {TARGET}
 
 Please note docker has no access to usb devices on MacOS. So the use of `cargo ledger build {TARGET} --load` will fail.
 
-### Install `ledger`
+### Manual installation
 
 - First delete the application if it was already installed
 
@@ -54,8 +109,9 @@ Please note docker has no access to usb devices on MacOS. So the use of `cargo l
 ```
 `ledgerctl install app_nanosplus.json`
 ```
+
 **Note:** In some cases the `cargo ledger build` action will invalidate `app_nanosplus.json` by setting the first line
-to `"apiLevel": "0",` - ensure it is set to `"apiLevel": "1",`
+to something other than `"apiLevel": "1",` - ensure it is set to `"apiLevel": "1",`
 
 ### Running the ledger application
 

applications/minotari_ledger_wallet/wallet/src/main.rs

@@ -35,7 +35,6 @@ use handlers::{
     get_public_key::handler_get_public_key,
     get_script_offset::{handler_get_script_offset, ScriptOffsetCtx},
     get_script_signature::handler_get_script_signature,
-    get_script_signature_from_challenge::handler_get_script_signature_from_challenge,
     get_version::handler_get_version,
     get_view_key::handler_get_view_key,
 };
@@ -177,7 +176,6 @@ impl TryFrom<ApduHeader> for Instruction {
                 more: value.p2 == P2_MORE,
             }),
             (0x07, 0, 0) => Ok(Instruction::GetMetadataSignature),
-            (0x08, 0, 0) => Ok(Instruction::GetScriptSignatureFromChallenge),
             (0x09, 0, 0) => Ok(Instruction::GetViewKey),
             (0x10, 0, 0) => Ok(Instruction::GetDHSharedSecret),
             (0x06, _, _) => Err(AppSW::WrongP1P2),
@@ -226,7 +224,6 @@ fn handle_apdu(comm: &mut Comm, ins: Instruction, offset_ctx: &mut ScriptOffsetC
         Instruction::GetScriptSignature => handler_get_script_signature(comm),
         Instruction::GetScriptOffset { chunk, more } => handler_get_script_offset(comm, chunk, more, offset_ctx),
         Instruction::GetMetadataSignature => handler_get_metadata_signature(comm),
-        Instruction::GetScriptSignatureFromChallenge => handler_get_script_signature_from_challenge(comm),
         Instruction::GetViewKey => handler_get_view_key(comm),
         Instruction::GetDHSharedSecret => handler_get_dh_shared_secret(comm),
     }