`cargo stylus new` panics when stylus-sdk is not discoverable

Description

While trying to create a new Stylus project using cargo stylus new, the command panics if the stylus-sdk package cannot be located, without providing a user-facing error message or guidance on how to resolve the issue.

Since this is typically the first command a new developer runs, the panic makes it difficult to understand what prerequisite is missing or how to proceed.

Steps to Reproduce

1. Ensure cargo-stylus is installed

2. Run:

   cargo stylus new example
   

3. Observe the panic during project creation

Observed Behavior

The command panics with the following error:

thread 'main' panicked at ... stylus_sdk.rs:51:10:
Finding stylus-sdk package

No actionable information is provided about:

• where stylus-sdk is expected to be found
• whether it is missing, misconfigured, or version-incompatible
• how the user should resolve the issue

Expected Behavior

Instead of panicking, the tool could:

• surface a clear error message indicating that stylus-sdk is missing or not discoverable
• document the requirement explicitly before project creation
• or provide guidance on how to install or configure the dependency

Environment

• OS: Windows (via WSL2 / Ubuntu)
• Rust version: 1.92.0
• cargo-stylus version: 0.10.0

Reproduce the failure with cargo stylus new example in the stated environment, then inspect the stylus_sdk.rs:51:10 path used during project creation. Trace how an undiscoverable stylus-sdk package is handled and add a user-facing error or guidance instead of a panic; done means the command reports the missing or misconfigured dependency clearly.