schema command missing eval and idle-timeout

[kiyeonjeon21]

snact schema output doesn't include:

1. eval command — implemented in CLI and MCP, but missing from schema.rs command list. Agents using schema introspection won't discover it.

2. idle_timeout param on browser launch — implemented in CLI but not reflected in schema output.

Where to fix

• crates/snact-cli/src/cmd/schema.rs — add eval to the command match and idle_timeout to browser launch schema.