fix(sandbox): spawn confined argv directly (round 1)

docs/config-catalog.md

@@ -216,7 +216,7 @@ export interface Config {
 }
 ```
 
-Source: [`packages/bash/bash-local/src/index.ts:39`](../packages/bash/bash-local/src/index.ts)
+Source: [`packages/bash/bash-local/src/index.ts:40`](../packages/bash/bash-local/src/index.ts)
 
 ## `@deepseek-ai/dsh-bash-sandbox`
 
@@ -235,7 +235,7 @@ export type Config = LocalConfig
 
 Depends on: [`LocalConfig`](#deepseek-aidsh-bash-local)
 
-Source: [`packages/bash/bash-sandbox/src/index.ts:34`](../packages/bash/bash-sandbox/src/index.ts)
+Source: [`packages/bash/bash-sandbox/src/index.ts:35`](../packages/bash/bash-sandbox/src/index.ts)
 
 ## `@deepseek-ai/dsh-cli-demo`
 
@@ -1019,17 +1019,17 @@ export interface Config {
   /**
    * Override the runner argv; bwrap-shaped profile arguments are appended. A
    * non-empty override asserts full enforcement and skips built-in selection and
-   * probing; a broken runner then fails at execution and must be identifiable by
-   * {@link runnerFailureSignatures}.
+   * probing. A runner that starts but refuses its profile must be identifiable by
+   * {@link runnerFailureSignatures}; spawn rejection remains a consumer-owned
+   * infrastructure failure.
    */
   runnerCommand?: string[]
   /**
    * Case-insensitive stderr substrings emitted when a configured
    * {@link runnerCommand} refuses its profile before executing the wrapped
    * command. Required and non-empty with `runnerCommand`; rejected without
-   * it. Missing/unexecutable runner errors are added automatically from
-   * `runnerCommand[0]`, while these signatures cover an executable runner's
-   * own failure dialect.
+   * it. Each entry is a non-empty, single-line, case-insensitive substring
+   * covering the executable runner's own failure dialect.
    */
   runnerFailureSignatures?: string[]
   /** Positive timeout for each functional probe; zero would mean unbounded to Node. */
@@ -1037,7 +1037,7 @@ export interface Config {
 }
 ```
 
-Source: [`packages/sandbox/sandbox-local/src/index.ts:24`](../packages/sandbox/sandbox-local/src/index.ts)
+Source: [`packages/sandbox/sandbox-local/src/index.ts:25`](../packages/sandbox/sandbox-local/src/index.ts)
 
 ## `@deepseek-ai/dsh-sandbox-policy`