Initial template: release pipeline + PORTING.md + init helper

What lands in any repo created from this template:
- .gitea/workflows/release.yml — canonical Gitea-Actions release pipeline
  (tag-triggered, curl-based publish, per-asset failure tolerance)
- tools/build_zip.sh — git-archive per addon folder, multi-addon bundle
- tools/init_from_upstream.sh — one-shot squash-import of upstream tree
  into <AddonFolder>/ at the repo root
- PORTING.md — full CoA-compat bug-pattern checklist (Retail-only
  globals, FileDataIDs, hardcoded class lists, StaticPopup race,
  .tga textures, Minimap mask, CLEU arg positions, Ace3 sweep, etc.)
- README.md — quick-start backport guide
- standard .gitignore (incl dist/) + .gitattributes (* -text)

tools/build_zip.sh

@@ -0,0 +1,71 @@
+#!/usr/bin/env bash
+# Build per-addon zip artefacts from HEAD via git-archive.
+#
+# - Discovers top-level addon folders (Foo/Foo.toc).
+# - Re-creates dist/ each run.
+# - Always archives HEAD, so the working tree state is irrelevant.
+# - If more than one addon folder is present, also emits <repo>-all.zip
+#   with every addon folder side-by-side at the zip root.
+# - When run inside Gitea Actions the working tree lives under a
+#   per-job dir like /var/lib/act_runner/work/.../hostexecutor, so the
+#   repo name comes from $GITHUB_REPOSITORY (set by the runner) and
+#   only falls back to the toplevel basename for local invocations.
+set -euo pipefail
+
+root=$(git rev-parse --show-toplevel)
+cd "$root"
+
+# Gitea Actions sets GITHUB_REPOSITORY=owner/repo. The basename of
+# `git rev-parse --show-toplevel` inside the runner is the worker dir
+# (e.g. `hostexecutor`), which would name the bundle wrong.
+if [ -n "${GITHUB_REPOSITORY:-}" ]; then
+    repo_name="${GITHUB_REPOSITORY##*/}"
+else
+    repo_name=$(basename "$root")
+fi
+dist="$root/dist"
+
+# Find Foo/Foo.toc pairs at depth 1; ignore libs nested deeper.
+addons=()
+while IFS= read -r toc; do
+    dir=$(dirname "$toc")
+    folder=$(basename "$dir")
+    base=$(basename "$toc" .toc)
+    # Accept Foo.toc and Foo_Wrath.toc style flavour variants; folder must match
+    # at least one toc basename prefix (Foo).
+    case "$base" in
+        "$folder"|"$folder"_*) addons+=("$folder") ;;
+    esac
+done < <(command find . -mindepth 2 -maxdepth 2 -type f -name '*.toc' | sed 's|^\./||' | sort)
+
+# Dedupe (a folder with Foo.toc + Foo_Wrath.toc shows up twice).
+if [ ${#addons[@]} -gt 0 ]; then
+    mapfile -t addons < <(printf '%s\n' "${addons[@]}" | awk '!seen[$0]++')
+fi
+
+if [ ${#addons[@]} -eq 0 ]; then
+    echo "no addon folders found (looking for */Foo.toc with matching folder name)" >&2
+    exit 1
+fi
+
+rm -rf "$dist"
+mkdir -p "$dist"
+
+for folder in "${addons[@]}"; do
+    out="$dist/$folder.zip"
+    # No --prefix: the folder already sits at the repo root, so git-archive
+    # emits entries as <folder>/... which is exactly what
+    # Interface/AddOns/ expects after extraction.
+    git archive HEAD --format=zip -o "$out" -- "$folder"
+    echo "built dist/$folder.zip"
+done
+
+# Combined bundle only makes sense when there are multiple addons.
+if [ ${#addons[@]} -gt 1 ]; then
+    tmp=$(mktemp -d)
+    trap 'rm -rf "$tmp"' EXIT
+    git archive HEAD --format=tar -- "${addons[@]}" | tar -x -C "$tmp"
+    out="$dist/$repo_name-all.zip"
+    ( cd "$tmp" && zip -qr "$out" "${addons[@]}" )
+    echo "built dist/$repo_name-all.zip"
+fi