docs: add fork Windows build notes

Author: christso

AGENTS.md

@@ -2,6 +2,10 @@
 
 - To test opencode in the `packages/opencode` directory you can run `bun dev`
 
+## Fork Notes
+
+- Windows build notes for the EntityProcess fork: [fork/AGENTS.md](fork/AGENTS.md)
+
 ## Tool Calling
 
 - ALWAYS USE PARALLEL TOOLS WHEN APPLICABLE. Here is an example illustrating how to execute 3 parallel file reads in this chat environment:

fork/AGENTS.md

@@ -0,0 +1,40 @@
+# Fork Notes (EntityProcess)
+
+This document is fork-specific and is referenced by the root `AGENTS.md`.
+
+## Windows Build (CLI)
+
+### Requirements
+
+- Bun 1.3+
+- PowerShell (recommended)
+
+### Build the CLI (Windows only)
+
+From the repo root:
+
+```powershell
+# Stop any running opencode.exe (Windows locks the file)
+Get-Process opencode -ErrorAction SilentlyContinue | Stop-Process -Force
+
+# Clean previous outputs
+Remove-Item -Recurse -Force -ErrorAction SilentlyContinue packages\opencode\dist
+
+# Build current platform only
+bun run --cwd packages/opencode script/build.ts --single --skip-install
+```
+
+Expected output binary:
+
+- `packages/opencode/dist/opencode-windows-x64/bin/opencode.exe`
+
+### Running
+
+```powershell
+.\packages\opencode\dist\opencode-windows-x64\bin\opencode.exe --version
+```
+
+### Notes (Windows quirks)
+
+- If `rm -rf dist` fails inside the build script, it’s usually because `opencode.exe` is still running. Stop it first (see above).
+- If TypeScript typecheck fails in `packages/desktop` or `packages/enterprise` on Windows, it can be due to symlink checkout differences. In this fork, the `playground` branch includes a workaround for `custom-elements.d.ts` when symlinks are not available.