Harden the plugin system with safer loading behavior

[Nanle-code]

Summary:
The plugin system is an important extension point for the project, but it should be made more robust and predictable for real users.

Why this matters:
Plugins extend the CLI’s functionality, so reliability and safety in plugin loading are essential for long-term trust.

Proposed work:

• Review plugin load and registry behavior for edge cases
• Improve validation of plugin metadata and paths
• Add clearer error handling around incompatible or broken plugins

Acceptance criteria:

• Plugin loading behaves safely under expected conditions
• Broken plugins fail gracefully with clear diagnostics
• Plugin compatibility is easier to reason about

[Ejirowebfi]

@Ejirowebfi has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Full stacks
Hi, I'd like to apply for this issue.

I'm a full stack developer (3–5 years) comfortable across the entire stack — from database schema and API design to React/TypeScript frontend and deployment. I regularly work on features that touch both layers, so I'm used to tracing bugs that cross the frontend/backend boundary.

For this specific issue, I plan to: [e.g. audit the API response shape, fix the mismatch on the server side, then update the frontend to handle the corrected structure and add a test for both layers]. I've worked with [technologies mentioned in the issue].

My availability is [X hrs/week]. Estimated completion: [X hours/days].

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Ejirowebfi to this issue.