refactor(git): split runner.ts into focused command-runner modules (#16395)

* refactor(git): split runner.ts into focused command-runner modules

* chore(ratchets): repoint child_process and wsl.exe allowlists at the split modules

---------

Co-authored-by: Neil <n@example.com>

src/main/git/command-runner/github-cli-host-fallback.ts

@@ -0,0 +1,93 @@
+import type { ResolvedCommand } from './wsl-command-resolution'
+
+function hasExplicitRepoArg(args: string[]): boolean {
+  for (let i = 0; i < args.length; i++) {
+    if (
+      (args[i] === '--repo' || args[i] === '-R') &&
+      typeof args[i + 1] === 'string' &&
+      args[i + 1].trim()
+    ) {
+      return true
+    }
+    if (args[i].startsWith('--repo=') || args[i].startsWith('-R=')) {
+      return args[i].slice(args[i].indexOf('=') + 1).trim().length > 0
+    }
+    if (args[i].startsWith('-R') && args[i].length > 2) {
+      return args[i].slice(2).trim().length > 0
+    }
+  }
+  return false
+}
+
+function argsUseGhApiPlaceholders(args: string[]): boolean {
+  return args.some(
+    (arg) => arg.includes('{owner}') || arg.includes('{repo}') || arg.includes('{branch}')
+  )
+}
+
+function hasExplicitRepoViewTarget(args: string[]): boolean {
+  const target = args[2]
+  return (
+    args[0] === 'repo' &&
+    args[1] === 'view' &&
+    typeof target === 'string' &&
+    !target.startsWith('-') &&
+    target.includes('/')
+  )
+}
+
+function canRunGitHubCliWithoutRepoCwd(args: string[]): boolean {
+  if (hasExplicitRepoArg(args)) {
+    return true
+  }
+  if (args[0] === 'api') {
+    return !argsUseGhApiPlaceholders(args)
+  }
+  return args[0] === 'auth' || hasExplicitRepoViewTarget(args)
+}
+
+function isMissingCommandInWsl(stderr: string, command: string): boolean {
+  const s = stderr.toLowerCase()
+  const c = command.toLowerCase()
+  return s.includes(`${c}: command not found`) || s.includes(`${c}: not found`)
+}
+
+export function canFallBackToHostGitHubCli(
+  command: 'gh',
+  args: string[],
+  resolved: ResolvedCommand,
+  stderr: string
+): boolean {
+  return (
+    process.platform === 'win32' &&
+    resolved.wsl !== null &&
+    isMissingCommandInWsl(stderr, command) &&
+    canRunGitHubCliWithoutRepoCwd(args)
+  )
+}
+
+export function resolveHostGitHubCli(command: 'gh', args: string[]): ResolvedCommand {
+  return {
+    binary: command,
+    args,
+    // Why: host gh can't use a WSL UNC cwd; we only fall back for commands with explicit repo/API context, so none is needed.
+    cwd: undefined,
+    wsl: null,
+    wslMode: null
+  }
+}
+
+export function isHostCommandMissing(err: unknown, command: 'gh' | 'glab'): boolean {
+  if (!err || typeof err !== 'object') {
+    return false
+  }
+  const e = err as { code?: unknown; message?: unknown; syscall?: unknown; path?: unknown }
+  if (e.code === 'ENOENT') {
+    return true
+  }
+  const message = typeof e.message === 'string' ? e.message.toLowerCase() : ''
+  return (
+    message.includes('enoent') &&
+    (message.includes(command) || e.path === command || e.syscall === 'spawn')
+  )
+}