feat(distribution): binary release pipeline + brew + winget

- .github/workflows/release-cli.yml: build self-contained binaries via
  `bun build --compile` for darwin/linux/windows × x64/arm64 on every
  cli-v* tag, attach to GitHub Release with SHA256SUMS, auto-bump the
  homebrew tap on non-prerelease versions.
- packaging/homebrew/claudemesh.rb.template: formula template for the
  homebrew-claudemesh tap.
- packaging/winget/claudemesh.yaml.template: winget manifest template.
- /install script now detects absence of Node and downloads the
  platform-appropriate binary from the GitHub Release, installs to
  ~/.claudemesh/bin, and shims into ~/.local/bin — zero Node required.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/web/src/app/install/route.ts

@@ -30,42 +30,87 @@ say "\${BOLD}claudemesh-cli installer\${RESET}"
 say "$(printf '%.0s─' {1..40})"
 
 # --- preflight ------------------------------------------------------
+# Prefer npm when Node 20+ is present. Otherwise fall back to a
+# self-contained binary download from GitHub Releases (installs to
+# ~/.claudemesh/bin and adds a shim at ~/.local/bin/claudemesh).
 
-if ! command -v node >/dev/null 2>&1; then
-  err "Node.js is not installed."
-  say "   Install Node.js 20 or newer: \${BOLD}https://nodejs.org\${RESET}"
-  say "   Or via nvm: \${DIM}curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.40.1/install.sh | bash\${RESET}"
-  exit 1
+detect_os() {
+  case "$(uname -s)" in
+    Darwin) echo darwin ;;
+    Linux)  echo linux  ;;
+    *)      echo ""     ;;
+  esac
+}
+detect_arch() {
+  case "$(uname -m)" in
+    x86_64|amd64)  echo x64   ;;
+    arm64|aarch64) echo arm64 ;;
+    *)             echo ""    ;;
+  esac
+}
+
+install_via_binary() {
+  local os arch url target dir shim
+  os=$(detect_os); arch=$(detect_arch)
+  if [ -z "$os" ] || [ -z "$arch" ]; then
+    err "No precompiled binary for $(uname -s)/$(uname -m). Install Node 20+ or build from source."
+    exit 1
+  fi
+  dir="\${HOME}/.claudemesh/bin"
+  mkdir -p "$dir"
+  target="\${dir}/claudemesh"
+  url="https://github.com/alezmad/claudemesh/releases/latest/download/claudemesh-\${os}-\${arch}"
+  say "Downloading \${BOLD}\${url}\${RESET}…"
+  if ! curl -fsSL "$url" -o "$target"; then
+    err "Download failed. Falling back to npm."
+    return 1
+  fi
+  chmod +x "$target"
+  shim="\${HOME}/.local/bin/claudemesh"
+  mkdir -p "\${HOME}/.local/bin"
+  printf '#!/bin/sh\\nexec "%s" "$@"\\n' "$target" > "$shim"
+  chmod +x "$shim"
+  ok "claudemesh binary installed → \${target}"
+  case ":$PATH:" in
+    *":\${HOME}/.local/bin:"*) : ;;
+    *)
+      say ""
+      say "\${BOLD}Add \${HOME}/.local/bin to PATH\${RESET} (add to your shell rc):"
+      say "  export PATH=\\"\${HOME}/.local/bin:\$PATH\\""
+      ;;
+  esac
+  return 0
+}
+
+install_via_npm() {
+  ok "Node.js $(node -v)"
+  ok "npm $(npm -v)"
+  say ""
+  say "Installing \${BOLD}claudemesh-cli\${RESET} from npm…"
+  if ! npm install -g claudemesh-cli; then
+    err "npm install failed."
+    say "   If this is a permissions error on macOS/Linux, try:"
+    say "   \${DIM}sudo npm install -g claudemesh-cli\${RESET}"
+    say "   or configure npm to use a user-owned prefix:"
+    say "   \${DIM}https://docs.npmjs.com/resolving-eacces-permissions-errors\${RESET}"
+    exit 1
+  fi
+  ok "claudemesh-cli installed ($(claudemesh --version))"
+}
+
+if command -v node >/dev/null 2>&1; then
+  NODE_MAJOR=$(node -p "process.versions.node.split('.')[0]" 2>/dev/null || echo 0)
+  if [ "$NODE_MAJOR" -ge 20 ] && command -v npm >/dev/null 2>&1; then
+    install_via_npm
+  else
+    say "Node.js < 20 or no npm — using standalone binary."
+    install_via_binary || install_via_npm
+  fi
+else
+  say "Node.js not detected — installing standalone binary (no Node required)."
+  install_via_binary
 fi
 
-NODE_MAJOR=$(node -p "process.versions.node.split('.')[0]")
-if [ "$NODE_MAJOR" -lt 20 ]; then
-  err "Node.js $(node -v) is too old — claudemesh-cli needs >= 20."
-  say "   Upgrade: \${BOLD}https://nodejs.org\${RESET}"
-  exit 1
-fi
-ok "Node.js $(node -v)"
-
-if ! command -v npm >/dev/null 2>&1; then
-  err "npm is not installed (usually ships with Node)."
-  exit 1
-fi
-ok "npm $(npm -v)"
-
-# --- install --------------------------------------------------------
-
-say ""
-say "Installing \${BOLD}claudemesh-cli\${RESET} from npm…"
-if ! npm install -g claudemesh-cli; then
-  err "npm install failed."
-  say "   If this is a permissions error on macOS/Linux, try:"
-  say "   \${DIM}sudo npm install -g claudemesh-cli\${RESET}"
-  say "   or configure npm to use a user-owned prefix:"
-  say "   \${DIM}https://docs.npmjs.com/resolving-eacces-permissions-errors\${RESET}"
-  exit 1
-fi
-ok "claudemesh-cli installed ($(claudemesh --version))"
-
 # --- register MCP + hooks ------------------------------------------
 
 say ""