fix(code): clean native sandbox state when spawn does not settle #128

After wrapWithSandboxArgv succeeds, per-command SRT cleanup currently runs only from runWrapped settlement. An abort between wrapping and spawning, or a synchronous spawn throw, can leave command state allocated until a later command or close().

Source: #101, packages/code/src/native-sandbox.ts around wrap/spawn and cleanupAfterCommand.

Please guarantee cleanup on all pre-settlement exits and add focused abort/spawn-throw coverage.