chore(cli): initialize rnr with all platforms

Adds .rnr directory with binaries for all platforms and wrapper scripts
for dogfooding during development.

Author: CalvinAllen

.rnr/bin/rnr-linux-amd64

@@ -0,0 +1,7 @@
+version: 0.1.0
+platforms:
+- linux-amd64
+- macos-amd64
+- macos-arm64
+- windows-amd64
+- windows-arm64

.rnr/bin/rnr-macos-amd64

@@ -0,0 +1,30 @@
+#!/bin/sh
+set -e
+
+# Detect OS
+OS=$(uname -s | tr '[:upper:]' '[:lower:]')
+EXT=""
+case "$OS" in
+  linux*) OS="linux" ;;
+  darwin*) OS="macos" ;;
+  mingw*|msys*|cygwin*) OS="windows"; EXT=".exe" ;;
+  *) echo "Error: Unsupported OS: $OS" >&2; exit 1 ;;
+esac
+
+# Detect architecture
+ARCH=$(uname -m)
+case "$ARCH" in
+  x86_64|amd64) ARCH="amd64" ;;
+  arm64|aarch64) ARCH="arm64" ;;
+  *) echo "Error: Unsupported architecture: $ARCH" >&2; exit 1 ;;
+esac
+
+BINARY="$(dirname "$0")/.rnr/bin/rnr-${OS}-${ARCH}${EXT}"
+
+if [ ! -f "$BINARY" ]; then
+  echo "Error: rnr is not configured for ${OS}-${ARCH}." >&2
+  echo "Run 'rnr init --add-platform ${OS}-${ARCH}' to add support." >&2
+  exit 1
+fi
+
+exec "$BINARY" "$@"

.rnr/bin/rnr-macos-arm64

@@ -0,0 +1,19 @@
+@echo off
+setlocal
+
+:: Detect architecture
+if "%PROCESSOR_ARCHITECTURE%"=="ARM64" (
+  set "ARCH=arm64"
+) else (
+  set "ARCH=amd64"
+)
+
+set "BINARY=%~dp0.rnr\bin\rnr-windows-%ARCH%.exe"
+
+if not exist "%BINARY%" (
+  echo Error: rnr is not configured for windows-%ARCH%. >&2
+  echo Run 'rnr init --add-platform windows-%ARCH%' to add support. >&2
+  exit /b 1
+)
+
+"%BINARY%" %*