fix: spawn cursor-agent with shell mode on Windows (model discovery falls back to static list)

[Cyctes-X]

Problem

On Windows, cursor-agent is installed as a .cmd shim
(%LOCALAPPDATA%\cursor-agent\cursor-agent.cmd). Node's execFileSync cannot
execute a bare .cmd file and throws EINVAL:

spawnSync C:\Users\...\AppData\Local\cursor-agent\cursor-agent.cmd EINVAL

Because of this, every model-discovery path silently fell back to the static
20-model list:

• open-cursor install / open-cursor sync-models -> "Models synced: 20"
• plugin startup auto-refresh -> never adds newly released Cursor models
• open-cursor doctor -> misreports cursor-agent: not found / not logged in

Users on Windows therefore never see models that exist in their Cursor
subscription (e.g. the cursor-grok-4.5-* / cursor-grok-4.6-* families), even
though cursor-agent models lists 200+ models from a normal shell.

Root cause

src/utils/binary.ts documents the existing contract clearly:

callers pair this resolver with shell: process.platform === "win32" at every
Node spawn site

plugin.ts follows it (spawnSync(..., shell: process.platform === "win32")),
but cli/model-discovery.ts and the doctor checks in cli/opencode-cursor.ts
did not.

Fix

• src/cli/model-discovery.ts:
  • discoverModelsFromCursorAgent() now spawns with shell: platform === "win32"
  • added an injectable deps object (platform / execFileSync /
    resolveBinary) so the spawn behaviour is unit-testable
• src/cli/opencode-cursor.ts: checkCursorAgent() and
  checkCursorAgentLogin() use the same shell: process.platform === "win32"
  so open-cursor doctor works on Windows

Testing

• New unit tests in tests/unit/cli/model-discovery.test.ts assert:
  • win32 -> shell: true and the resolved .cmd binary is used
  • non-win32 -> shell: false and killSignal: SIGTERM (unchanged behaviour)
• bun test tests/unit/cli/model-discovery.test.ts -> 4 pass
• Verified on Windows x64: open-cursor sync-models --dry-run now
  discovers 204 models (previously 20 via fallback) and writes
  cursor-grok-4.5-high / cursor-grok-4.6-* into opencode.json; latest
  open-cursor doctor reports cursor-agent installed/logged in.

Notes

• dist/ is git-ignored and rebuilt at publish time, so no build artifacts are
  committed.
• The only unrelated failure in the Windows test suite is a pre-existing
  symlinkSync EPERM in tests/unit/cli/opencode-cursor.test.ts (Windows
  requires Developer Mode / admin for symlinks) -> unrelated to this change.

[Nomadcxx]

Thanks for tracking this down. You found the right root cause and CI is green. Every discovery path routes through discoverModelsFromCursorAgent, so the one fix covers sync-models, install, and startup refresh.

One gap: binary.ts asks callers to pair shell: true with formatShellCommandForPlatform(), and the three new spawn sites only do the first half. On a Windows profile with a space in the username, cmd.exe splits the unquoted .cmd path and discovery drops back to the static 20-model list. Same thing came up in #73, fixed in 34339dc.

I'll merge this as the foundation and wrap the three sites in a maintainer follow-up, so you don't need to touch anything here.

Thanks again.

cheers, RAMA