Add OS-aware runtime context for cross-platform shell execution

Detect the runtime platform and default shell at startup, inject
platform context into assistant instructions, and replace hardcoded
/bin/sh with the detected shell in command executors (cli + electron).

Made-with: Cursor

apps/cli/src/application/assistant/runtime-context.ts

@@ -0,0 +1,69 @@
+export type RuntimeShellDialect = 'windows-cmd' | 'posix-sh';
+export type RuntimeOsName = 'Windows' | 'macOS' | 'Linux' | 'Unknown';
+
+export interface RuntimeContext {
+  platform: NodeJS.Platform;
+  osName: RuntimeOsName;
+  shellDialect: RuntimeShellDialect;
+  shellExecutable: string;
+}
+
+export function getExecutionShell(platform: NodeJS.Platform = process.platform): string {
+  return platform === 'win32' ? (process.env.ComSpec || 'cmd.exe') : '/bin/sh';
+}
+
+export function getRuntimeContext(platform: NodeJS.Platform = process.platform): RuntimeContext {
+  if (platform === 'win32') {
+    return {
+      platform,
+      osName: 'Windows',
+      shellDialect: 'windows-cmd',
+      shellExecutable: getExecutionShell(platform),
+    };
+  }
+
+  if (platform === 'darwin') {
+    return {
+      platform,
+      osName: 'macOS',
+      shellDialect: 'posix-sh',
+      shellExecutable: getExecutionShell(platform),
+    };
+  }
+
+  if (platform === 'linux') {
+    return {
+      platform,
+      osName: 'Linux',
+      shellDialect: 'posix-sh',
+      shellExecutable: getExecutionShell(platform),
+    };
+  }
+
+  return {
+    platform,
+    osName: 'Unknown',
+    shellDialect: 'posix-sh',
+    shellExecutable: getExecutionShell(platform),
+  };
+}
+
+export function getRuntimeContextPrompt(runtime: RuntimeContext): string {
+  if (runtime.shellDialect === 'windows-cmd') {
+    return `## Runtime Platform (CRITICAL)
+- Detected platform: **${runtime.platform}**
+- Detected OS: **${runtime.osName}**
+- Shell used by executeCommand: **${runtime.shellExecutable}** (Windows Command Prompt / cmd syntax)
+- Use Windows command syntax for executeCommand (for example: \`dir\`, \`type\`, \`copy\`, \`move\`, \`del\`, \`rmdir\`).
+- Use Windows-style absolute paths when outside workspace (for example: \`C:\\Users\\...\`).
+- Do not assume macOS/Linux command syntax when the runtime is Windows.`;
+  }
+
+  return `## Runtime Platform (CRITICAL)
+- Detected platform: **${runtime.platform}**
+- Detected OS: **${runtime.osName}**
+- Shell used by executeCommand: **${runtime.shellExecutable}** (POSIX sh syntax)
+- Use POSIX command syntax for executeCommand (for example: \`ls\`, \`cat\`, \`cp\`, \`mv\`, \`rm\`).
+- Use POSIX paths when outside workspace (for example: \`~/Desktop\`, \`/Users/.../\` on macOS, \`/home/.../\` on Linux).
+- Do not assume Windows command syntax when the runtime is POSIX.`;
+}