Address review feedback on the Amiga packaging PR.

Keep Amiga-specific files under amiga/, cache the pinned LHa binary in
CI, and make it explicit that the workflow artifact is not an official
release.

Co-authored-by: Cursor <cursoragent@cursor.com>

amiga/package-amiga.sh

@@ -0,0 +1,72 @@
+#!/usr/bin/env bash
+# Build every json-c variant for the requested Amiga systems and package them
+# into dist/json-c.lha.
+#
+#   ./amiga/package-amiga.sh [OS ...]     # default: all three
+#
+# Archive layout (single directory at the root):
+#     json-c/json-c.readme
+#     json-c/AmigaOS3/...    per-OS libraries and headers
+#     json-c/AmigaOS4/...
+#     json-c/MorphOS/...
+set -uo pipefail
+
+AMIGA_DIR=$(cd "$(dirname "$0")" && pwd)
+ROOT=$(cd "$AMIGA_DIR/.." && pwd)
+cd "$ROOT"
+DIST=$ROOT/dist
+STAGE=$DIST/stage
+OSES=("$@"); [[ ${#OSES[@]} -eq 0 ]] && OSES=(AmigaOS3 AmigaOS4 MorphOS)
+
+command -v lha >/dev/null || { echo "error: lha not found on PATH" >&2; exit 1; }
+# Ubuntu's `lha` package is lhasa, which can only extract.
+_lha_probe=$(mktemp -d)
+echo x > "$_lha_probe/f"
+if ! ( cd "$_lha_probe" && lha -aq2 t.lha f >/dev/null 2>&1 && [[ -s t.lha ]] ); then
+  echo "error: lha cannot create archives (is it lhasa?). Install LHa for UNIX: https://github.com/jca02266/lha" >&2
+  rm -rf "$_lha_probe"
+  exit 1
+fi
+rm -rf "$_lha_probe"
+
+# Build straight into the staging tree by pointing AMIGA_SDK at it: the build
+# script's SDK layout ($SDK/<target>) is the same shape we want per OS, so each
+# OS gets staged under its own directory.
+rm -rf "$DIST"; mkdir -p "$STAGE/json-c"
+cp "$AMIGA_DIR/json-c.readme" "$STAGE/json-c/json-c.readme"
+
+built=()
+for os in "${OSES[@]}"; do
+  case "$os" in
+    AmigaOS3) sub=m68k-amigaos ;;
+    AmigaOS4) sub=ppc-amigaos ;;
+    MorphOS)  sub=ppc-morphos ;;
+    *) echo "skip: unknown OS $os"; continue ;;
+  esac
+  tmp=$DIST/sdk-$os
+  mkdir -p "$tmp/$sub"
+  echo "=== $os ==="
+  # Stage whatever landed even if some variants failed -- a single unsupported
+  # multilib should not drop the whole OS from the archive.
+  AMIGA_SDK="$tmp" "$AMIGA_DIR/build-amiga-sdk.sh" "$os" || echo "  ($os: some variants failed, see above)"
+  if [[ -n $(find "$tmp/$sub" -name 'libjson-c.a' -print -quit 2>/dev/null) ]]; then
+    mkdir -p "$STAGE/json-c/$os"
+    cp -a "$tmp/$sub/." "$STAGE/json-c/$os/"
+    built+=("$os")
+  else
+    echo "  $os: nothing built, omitted from the archive"
+  fi
+  rm -rf "$tmp"
+done
+
+[[ ${#built[@]} -eq 0 ]] && { echo "nothing built"; exit 1; }
+
+# NOTE: build the archive from a clean staging tree with `lha -aq2`. Do NOT try
+# to refresh a single entry (e.g. the readme) in an existing archive with
+# `lha u` -- it APPENDS a second entry with the same name rather than replacing
+# it, and extraction then yields the stale copy.
+( cd "$STAGE" && lha -aq2 "$DIST/json-c.lha" * >/dev/null )
+rm -rf "$STAGE"
+echo
+echo "packaged: ${built[*]}"
+ls -la "$DIST"