fix: use cargo stylus CLI instead of plain cargo check/build

[keruch]

After creating a project, AI tries to check if it compiles using cargo check without --target wasm32-unknown-unknown. Compilation fails, and AI falls into an infinite loop of resolving dependency issues.

[dtr0x]

The fix should use cargo stylus check rather than raw cargo check/build with manual flags:

• cargo stylus check already handles this. It internally runs cargo build --release --target wasm32-unknown-unknown with the -Z build-std flags (when nightly is detected), then validates the WASM on-chain. It's already in the skill under "Build & Deploy Basics."
• cargo stylus build doesn't exist as a subcommand. check does the full compile.
• The -Z build-std flags are conditional. cargo stylus check auto-detects nightly vs stable. Hardcoding them could break on stable toolchains.
• Consistency. The skill uses cargo stylus for everything else (new, export-abi, deploy). Adding raw cargo commands teaches the agent the wrong workflow.

The root cause is that cargo stylus check appears too late in the skill (under "Build & Deploy"), so the agent doesn't see it right after project creation. A better fix would be adding a note right after cargo stylus new like:

After creating the project, verify it compiles with cargo stylus check (see Build & Deploy section below). Do NOT use plain cargo check or cargo build, since Stylus contracts require the cargo stylus CLI for correct WASM compilation.

This addresses the agent behavior without introducing commands that bypass the purpose-built tooling.

[keruch]

@dtr0x thank you for the review, it totally makes sense! Updated the PR with your suggestion.

[ericglau]

LGTM, thanks!

[ericglau]

Hi @keruch, thanks a lot for the PR and sorry for the delay. In order for us to merge this, the commits need to be signed. Would you be able to sign and re-push your commits?