spike(embedded-mpv): support MacPorts libmpv and legacy-macOS bundles

Makefile and collect-results.sh now detect libmpv in the Homebrew prefix or
MacPorts /opt/local (Homebrew is unsupported on legacy macOS like High
Sierra; 'sudo port install mpv +libmpv' provides libmpv there). make-bundle
takes ELECTRON_VERSION/BUNDLE_SUFFIX overrides — Electron 27+ needs macOS
10.15, so High Sierra bundles ship Electron 26.6.10 (LSMinimumSystemVersion
10.13).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

spikes/mpv-frame-copy/Makefile

@@ -5,7 +5,15 @@
 # if detection picks the wrong one. Works on Apple Silicon (/opt/homebrew)
 # and Intel (/usr/local) Homebrew layouts.
 
-BREW_PREFIX ?= $(shell brew --prefix 2>/dev/null || echo /opt/homebrew)
+# libmpv prefix: Homebrew (Apple Silicon /opt/homebrew or Intel /usr/local)
+# or MacPorts (/opt/local, needed on legacy macOS like High Sierra where
+# Homebrew is unsupported — install with: sudo port install mpv +libmpv).
+MPV_PREFIX ?= $(shell \
+	brew_p="$$(brew --prefix 2>/dev/null)"; \
+	if [ -n "$$brew_p" ] && ls "$$brew_p"/lib/libmpv*.dylib >/dev/null 2>&1; then echo "$$brew_p"; \
+	elif ls /opt/local/lib/libmpv*.dylib >/dev/null 2>&1; then echo /opt/local; \
+	else echo /opt/homebrew; fi)
+BREW_PREFIX ?= $(MPV_PREFIX)
 # Self-contained bundles vendor the four N-API headers so no Node install
 # is needed; otherwise take headers from the PATH node.
 ifneq (,$(wildcard vendor/node-headers/node_api.h))

spikes/mpv-frame-copy/collect-results.sh

@@ -22,9 +22,16 @@ if ! xcode-select -p >/dev/null 2>&1; then
     echo "Xcode Command Line Tools required: run 'xcode-select --install'" >&2
     exit 1
 fi
-BREW_PREFIX="$(brew --prefix 2>/dev/null || true)"
-if [[ -z "$BREW_PREFIX" || (! -e "$BREW_PREFIX/lib/libmpv.dylib" && ! -e "$BREW_PREFIX/lib/libmpv.2.dylib") ]]; then
-    echo "Homebrew libmpv required: run 'brew install mpv'" >&2
+MPV_PREFIX=""
+for prefix in "$(brew --prefix 2>/dev/null || true)" /opt/local; do
+    if [[ -n "$prefix" ]] && ls "$prefix"/lib/libmpv*.dylib >/dev/null 2>&1; then
+        MPV_PREFIX="$prefix"
+        break
+    fi
+done
+if [[ -z "$MPV_PREFIX" ]]; then
+    echo "libmpv not found. Install it with Homebrew ('brew install mpv') or," >&2
+    echo "on legacy macOS (e.g. High Sierra), MacPorts: 'sudo port install mpv +libmpv'" >&2
     exit 1
 fi
 

spikes/mpv-frame-copy/make-bundle.sh

@@ -6,15 +6,20 @@
 # Command Line Tools and `brew install mpv`.
 #
 #   ./make-bundle.sh [x64|arm64]      # Electron arch of the TARGET machine
+#
+# For legacy macOS targets override the Electron version — Electron 27+
+# requires macOS 10.15, Electron 26.6.10 is the last for 10.13/10.14:
+#   ELECTRON_VERSION=26.6.10 BUNDLE_SUFFIX=highsierra-x64 ./make-bundle.sh x64
 set -euo pipefail
 
 DIR="$(cd "$(dirname "$0")" && pwd)"
 cd "$DIR"
 
 ARCH="${1:-x64}"
-ELECTRON_VERSION="41.7.2"
+ELECTRON_VERSION="${ELECTRON_VERSION:-41.7.2}"
+BUNDLE_SUFFIX="${BUNDLE_SUFFIX:-$ARCH}"
 BUNDLE_ROOT="build/bundle/mpv-frame-copy-spike"
-TARBALL="build/mpv-frame-copy-spike-macos-$ARCH.tar.gz"
+TARBALL="build/mpv-frame-copy-spike-macos-$BUNDLE_SUFFIX.tar.gz"
 
 rm -rf build/bundle
 mkdir -p "$BUNDLE_ROOT"
@@ -69,7 +74,12 @@ cat > "$BUNDLE_ROOT/START-HERE.md" <<'EOF'
 Target-machine prerequisites (no Node/pnpm needed):
 
 1. Xcode Command Line Tools: `xcode-select --install`
-2. Homebrew mpv: `brew install mpv`
+2. libmpv, either via:
+    - Homebrew (macOS 13+): `brew install mpv`
+    - MacPorts (legacy macOS, e.g. High Sierra — install the MacPorts pkg
+      for your macOS from macports.org first):
+      `sudo port install mpv +libmpv` (compiles from source; can take
+      an hour or more on old hardware)
 
 Then: