feat: add patch series, build scripts and release automation

scripts/prepare.sh

@@ -0,0 +1,64 @@
+#!/usr/bin/env bash
+# Check out the pinned Modrinth App release and apply every patch on top of it.
+#
+# The result lands in build/upstream on the `enhanced` branch and is what all
+# other scripts build from. Running this again always starts from a clean
+# upstream tree, so it is safe to repeat.
+
+. "$(dirname "${BASH_SOURCE[0]}")/common.sh"
+
+log "Upstream $UPSTREAM_REF from $UPSTREAM_REPO"
+
+if [ ! -d "$WORKTREE/.git" ]; then
+	log "Cloning into $WORKTREE"
+	mkdir -p "$(dirname "$WORKTREE")"
+	git clone --depth 1 --branch "$UPSTREAM_REF" "$UPSTREAM_REPO" "$WORKTREE"
+else
+	log "Fetching $UPSTREAM_REF into the existing checkout"
+	git -C "$WORKTREE" remote set-url origin "$UPSTREAM_REPO"
+	git -C "$WORKTREE" fetch --depth 1 --force origin "refs/tags/$UPSTREAM_REF:refs/tags/$UPSTREAM_REF"
+fi
+
+# `git am` refuses to run with a rebase or merge in progress, and a previous
+# run may have stopped on a conflict.
+git -C "$WORKTREE" am --abort 2>/dev/null || true
+
+log "Resetting to $UPSTREAM_REF"
+git -C "$WORKTREE" checkout --detach --force "$UPSTREAM_REF"
+git -C "$WORKTREE" branch -f "$PATCH_BRANCH" "$UPSTREAM_REF"
+git -C "$WORKTREE" checkout --force "$PATCH_BRANCH"
+git -C "$WORKTREE" reset --hard "$UPSTREAM_REF"
+git -C "$WORKTREE" clean -fdx -e node_modules -e target
+
+# `git am` needs an identity for the commits it creates.
+git -C "$WORKTREE" config user.name "Modrinth Enhanced"
+git -C "$WORKTREE" config user.email "patches@modrinth-enhanced.invalid"
+git -C "$WORKTREE" config commit.gpgsign false
+
+shopt -s nullglob
+patches=("$PATCH_DIR"/*.patch)
+shopt -u nullglob
+
+[ ${#patches[@]} -gt 0 ] || die "No patches found in $PATCH_DIR"
+
+log "Applying ${#patches[@]} patches"
+if ! git -C "$WORKTREE" am --3way --whitespace=nowarn "${patches[@]}"; then
+	cat >&2 <<EOF
+
+A patch did not apply to $UPSTREAM_REF.
+
+The failed patch is left staged in $WORKTREE so it can be fixed by hand:
+
+  cd $WORKTREE
+  git status                 # see the conflicts
+  # ...resolve them, then:
+  git add -A && git am --continue
+  # once every patch is in:
+  $REPO_ROOT/scripts/export-patches.sh
+
+EOF
+	exit 1
+fi
+
+log "Patched checkout ready at $WORKTREE"
+git -C "$WORKTREE" --no-pager log --oneline "$UPSTREAM_REF..$PATCH_BRANCH"