fix(windows): add qmd.cmd launcher that invokes node/bun directly

[OthmanAdi]

Problem

On Windows, the npm-generated qmd.cmd wrapper calls /bin/sh to run bin/qmd. When MCP clients (e.g. Claude Code, Cursor, or any tool using Node.js child_process.spawn()) start qmd as a stdio subprocess, /bin/sh is not reliably available — Git for Windows is often absent from the subprocess PATH even when present in interactive shells.

The result: qmd mcp silently fails to start when configured as an MCP stdio server. No error is shown to the user; the MCP client simply never sees the server.

Example broken config (fails on Windows via Node.js spawn):

{
  "mcpServers": {
    "qmd": { "command": "qmd", "args": ["mcp"] }
  }
}

Fix

Add bin/qmd.cmd: a native CMD launcher that mirrors the runtime-detection logic already in bin/qmd (checks package-lock.json → node, bun.lock / bun.lockb → bun, fallback → node) without requiring a POSIX shell.

npm uses a hand-crafted qmd.cmd over its auto-generated wrapper when both share the same base name — so this file is picked up automatically on npm install -g with no changes to package.json.

Verification

Tested via Node.js spawnSync (exactly how MCP clients spawn the server):

const r = spawnSync('cmd.exe', ['/c', 'qmd.cmd', '--help'], { encoding: 'utf8' });
// stdout: "qmd — Quick Markdown Search\n\nUsage:\n  qmd <command> [options]..."
// status: 0

MCP stdio handshake works end-to-end after this change.

Related

Similar in spirit to #555 (USERPROFILE fallback for Windows HOME resolution).