Windows: status_line.command containing double quotes is mangled by the cmd spawn

Summary

On Windows, a status_line.command containing double quotes (e.g. the Claude-Code-style py -3 "C:\path\to\statusline.py") is mangled before it reaches the shell: the command exits immediately and the footer silently falls back to the built-in layout. Any Windows user whose statusline command needs quoting — most commonly because the path contains spaces — cannot use the feature.

Root cause

apps/kimi-code/src/tui/utils/status-line-command.ts spawns the command as a single argv element:

spawn(isWin ? (process.env['ComSpec'] ?? 'cmd.exe') : 'sh', isWin ? ['/d', '/s', '/c', command] : ['-c', command], ...)

When libuv serializes that argv for CreateProcess, it wraps the command element in quotes and backslash-escapes any embedded ". cmd /s then strips only the outermost quote pair, leaving literal \" sequences in the executed line. The invoked program (MSVCRT-style argv parsing) reads those as escaped quote characters and glues tokens together. The interpreter ends up with a garbage path.

Reproduction (verbatim through the feature's own spawn path)

const { spawn } = require("node:child_process");
// Fails: quoted path (Claude Code's recommended form)
const cmd1 = 'py -3 "C:/Users/me/statusline.py"';
// Works: same command, unquoted
const cmd2 = 'py -3 C:/Users/me/statusline.py';

function tryIt(command) {
  const child = spawn(process.env.ComSpec ?? "cmd.exe", ["/d", "/s", "/c", command],
    { stdio: ["pipe", "pipe", "inherit"] });
  child.on("close", (code) => console.log(JSON.stringify(command), "-> exit", code));
  child.stdin.end(JSON.stringify({ model: "K3", cwd: "C:/x", gitBranch: null,
    permissionMode: "manual", planMode: false, contextUsage: 0,
    contextTokens: 0, maxContextTokens: 0, sessionId: "s", version: "0" }));
}
tryIt(cmd1); // exit 2 — python.exe: can't open file '...\\"C:\\...\\statusline.py"'
tryIt(cmd2); // exit 0

Observed on Windows 11, Node v22.19.0, kimi-code built from source at commit 67dd03149. Verified against the real spawn semantics above, and end-to-end in the built TUI (unquoted command renders the custom line correctly; quoted command exits 2 before producing any output).

Test gap

apps/kimi-code/test/tui/components/chrome/footer-status-line.test.ts only exercises POSIX commands (cat, true, printf, sleep) — no win32 case, and nothing with embedded quotes.

Suggested directions

• Spawn with shell: true (lets Node build the cmd /d /s /c "..." line itself), or
• Pre-wrap the command in an extra pair of quotes on Windows so the /s strip lands correctly, or
• If the constraint is intentional, document "no double quotes in status_line.command on Windows" — though that makes space-containing paths unusable, which quoted paths exist to solve.

Start in apps/kimi-code/src/tui/utils/status-line-command.ts and inspect the Windows spawn path, then review apps/kimi-code/test/tui/components/chrome/footer-status-line.test.ts for the existing command tests. Add coverage for a quoted Windows status-line command and verify that quoted paths work without breaking the existing POSIX cases; run the footer status-line test file to confirm the fix.