Missing RPC handler for openhuman.system_info method

[graycyrus]

Summary

The openhuman.system_info RPC method is not registered in the core dispatch, returning "unknown method" errors.

Problem

What happened: A client calls openhuman.system_info but the method isn't registered in the controller registry. Returns "unknown method".

Expected: The method should either be registered with a proper handler, or aliased to an existing method if it was renamed.

Impact: 1 event in Sentry (CORE-RUST-G0), Linux user.

Version / Platform: openhuman@0.56.0, Linux 6.8.0-111-generic, rustc 1.93.0

Solution (optional)

Same pattern as PR #2803 (MCP aliases) and PR #2853 (health_snapshot alias). Either:

1. Add a legacy alias in src/core/legacy_aliases.rs mapping to the correct method
2. Or register the method handler if it exists but isn't wired

Acceptance criteria

• Repro gone — openhuman.system_info resolves correctly
• Regression safety — Unit test for the alias/handler
• Diff coverage >= 80%

Related

• Sentry: https://sentry.tinyhumans.ai/organizations/tinyhumans/issues/6340/
• Prior art: PR fix(rpc): register missing MCP and tool registry RPC handlers #2803, PR fix(rpc): add health_snapshot legacy alias (Sentry CORE-RUST-FG, #2852) #2853