[Bug] Language servers installed with npm are reported as available but never start on Windows #1690

Description

On Windows, npm installs language servers (typescript-language-server, pyright, vscode-*-language-server) as .cmd shims. Nanocoder finds them with where (which understands .cmd) and reports them as available. But it then checks and starts them with execFileSync and spawn without a shell, and those cannot run a .cmd file. So no server starts and LSP features stay off. Only servers that ship as real .exe files (like gopls, rust-analyzer, clangd) should work.

Environment

• OS: Windows 11 (10.0.26300)
• Node version: 22.22.3
• Nanocoder version: 1.31.0 (main at 6eaff7a)
• typescript-language-server: 6.0.2, installed with npm install typescript-language-server typescript
• Provider / Model: not relevant

Steps to Reproduce

1. On Windows, run npm install typescript-language-server typescript and put node_modules\.bin on PATH.
2. Make a project with tsconfig.json and a.ts.
3. In that folder, call getKnownServersStatus() and discoverLanguageServers() from source/lsp/server-discovery.ts.
4. Compare with cmd /c typescript-language-server --version and with spawn('typescript-language-server', ['--stdio']).

Expected Behavior

The server is discovered and started, like it is on Linux and macOS.

Actual Behavior

where typescript-language-server        -> node_modules/.bin/typescript-language-server  |  .../typescript-language-server.cmd
cmd /c typescript-language-server --version      -> 6.0.2      (Windows can run it)
execFileSync('typescript-language-server', ...)  -> FAILS: ENOENT

getKnownServersStatus() ...  {"name":"typescript-language-server","available":true}
discoverLanguageServers()    []
spawn('typescript-language-server', ['--stdio'])  -> error event: ENOENT

Suggested Fix

• source/lsp/server-discovery.ts: findCommand (about lines 249-266) uses where, so it succeeds. verifyServer (about lines 274-290, execFileSync) and verifyLSPServerWithCommunication (about line 302, spawn) cannot run the shim. source/lsp/lsp-client.ts:69 has the same spawn.
• Use cross-spawn for all three. I checked that cross-spawn.sync('typescript-language-server', ['--version']) returns 6.0.2 here. Note that cross-spawn is only a transitive dependency today and is not imported anywhere in the repo, so add it to package.json (and keep knip happy).
• Or resolve <name>.cmd and run it through cmd.exe /d /s /c on win32. The node_modules/.bin fallback in findCommand finds the extensionless POSIX shim, which also can't be spawned on Windows.
• Add a Windows-only test: put a fake typescript-language-server.cmd on PATH and expect discoverLanguageServers() to return it. That exact test fails today.

Additional Context

• Related but different: [Bug] file:// URI parsing via slice(7) breaks Windows drive paths #1516 (file:// URI parsing on Windows), [Bug] Command not in Path #605 (closed, debug log noise).
• I have searched existing issues to ensure this is not a duplicate
• I can reproduce this issue consistently
• This issue occurs with the latest version of nanocoder