docs: document propchain-contracts public API — 9 missing ink! message doc comments (

[Ummi-001]

Closes #961
Closes #962
Closes #963
Closes #964

What

Adds /// doc comments to the 9 #[ink(message)] entry points in
contracts/lib/src/lib.rs that were missing documentation:

• get_external_dependency_breaker
• get_external_dependency_breaker_config
• configure_external_dependency_breaker
• trip_external_dependency_breaker
• reset_external_dependency_breaker
• grant_role
• revoke_role
• has_role
• get_permission_audit_entry

Each comment covers what the message does, caller/role requirements,
and the error variants it can return.

Why

propchain-contracts is the crate that docs.yml publishes as the
rustdoc landing page. These 9 messages were the only gap in its
public API docs.

Scope

Documentation only — no behavior changes, no SDK regeneration.

Testing

• cargo doc -p propchain-contracts --no-deps builds clean
• cargo test -p propchain-contracts passes

[drips-wave]

@Ummi-001 Great news! 🎉 Based on an automated assessment of this PR, the linked Wave issue(s) no longer count against your application limits.

You can now already apply to more issues while waiting for a review of this PR. Keep up the great work! 🚀

Learn more about application limits