P3.1: iOS goldens @2x + PNG optimizer + Makefile record/verify targets

- SnapshotGalleryTests rendered at displayScale: 2.0 (was native 3.0)
  → 49MB → 15MB (~69% reduction)
- Records via SNAPSHOT_TESTING_RECORD=1 env var (no code edits needed)
- scripts/optimize_goldens.sh runs zopflipng (or pngcrush fallback)
  over both iOS and Android golden dirs
- scripts/{record,verify}_snapshots.sh one-command wrappers
- Makefile targets: make {record,verify,optimize}-snapshots

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

scripts/verify_snapshots.sh

@@ -0,0 +1,57 @@
+#!/usr/bin/env bash
+#
+# verify_snapshots.sh — verify every parity-gallery golden matches the
+# current code. Use as a pre-commit / CI gate.
+#
+# Exits non-zero if either platform's gallery drifts from its committed
+# baseline. Diff artifacts land under each platform's usual report dir:
+#   Android:  composeApp/build/outputs/roborazzi/
+#   iOS:      ~/Library/Developer/Xcode/DerivedData/.../HoneyDueTests/
+#
+# Usage
+# -----
+#   ./scripts/verify_snapshots.sh               # both platforms
+#   ./scripts/verify_snapshots.sh --ios-only
+#   ./scripts/verify_snapshots.sh --android-only
+#
+set -euo pipefail
+
+cd "$(dirname "$0")/.."
+
+platform="both"
+for arg in "$@"; do
+    case "$arg" in
+        --ios-only)     platform="ios" ;;
+        --android-only) platform="android" ;;
+        -h|--help)
+            sed -n '3,14p' "$0"
+            exit 0
+            ;;
+        *)
+            echo "usage: $0 [--ios-only|--android-only]" >&2
+            exit 1
+            ;;
+    esac
+done
+
+# ---------- Android ----------
+if [ "$platform" = "both" ] || [ "$platform" = "android" ]; then
+    echo "==> Verifying Android goldens…"
+    ./gradlew :composeApp:verifyRoborazziDebug
+fi
+
+# ---------- iOS ----------
+if [ "$platform" = "both" ] || [ "$platform" = "ios" ]; then
+    echo "==> Verifying iOS goldens…"
+    (
+        cd iosApp
+        xcodebuild test \
+            -project honeyDue.xcodeproj \
+            -scheme HoneyDue \
+            -destination "${IOS_SIM_DESTINATION:-platform=iOS Simulator,name=iPhone 17,OS=latest}" \
+            -only-testing:HoneyDueTests/SnapshotGalleryTests \
+            2>&1 | tail -30
+    )
+fi
+
+echo "==> All snapshot checks passed."