feat(tool-script): add exec_command parameter schema with yield_time_ms and workdir

[MiMoHardFather]

Summary

Define a typed ExecCommandParameters schema (cmd, yield_time_ms, workdir) so exec_command no longer leaks bash's internal parameter names to code-mode callers. The args are translated via execCommandArgs before dispatch.

Changes

• Add ExecCommandParameters zod schema with cmd, yield_time_ms, and workdir fields
• Add execCommandArgs() helper that maps { cmd, yield_time_ms, workdir } → { command, timeout, workdir, description }
• Update generated type declarations to expose the new typed interface
• Update tool catalog description for exec_command to document the new parameters
• Update script guidance to reflect the new { cmd, yield_time_ms?, workdir? } interface
• Add tests for parameter mapping and default yield_time_ms of 10000 ms

Test plan

• exec_command maps to bash while direct bash remains backward compatible
• exec_command defaults yield_time_ms to 10000 ms
• Generated declarations use the new parameter schema
• Typecheck passes