Add .loop-build harness and IntelliJ project configuration files

.loop-build/scripts/snapshot.sh

@@ -0,0 +1,44 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
+LB_DIR="$ROOT_DIR/.loop-build"
+SNAP_DIR="$LB_DIR/state/snapshots"
+mkdir -p "$SNAP_DIR"
+label="${1:-manual}"
+mkdir -p "$LB_DIR/state"
+stamp="$(date -u +%Y%m%dT%H%M%SZ)"
+out="$SNAP_DIR/snapshot-${stamp}-${label}.json"
+
+if [[ -d "$ROOT_DIR/.git" ]]; then
+  head="$(git -C "$ROOT_DIR" rev-parse --short HEAD 2>/dev/null || true)"
+  if [[ -z "$head" ]]; then
+    head="NO_HEAD"
+  fi
+else
+  head="UNKNOWN"
+fi
+
+changed_lines=""
+if [[ -d "$ROOT_DIR/.git" ]]; then
+  changed_lines="$(git -C "$ROOT_DIR" status --porcelain --untracked-files=normal | cut -c4- | sed '/^$/d' | sort -u || true)"
+fi
+
+changed_json='[]'
+if [[ -n "$changed_lines" ]]; then
+  changed_json="$(printf '%s\n' "$changed_lines" | jq -R -s 'split("\n") | map(select(length > 0))')"
+fi
+
+jq -n \
+  --arg timestamp "$(date -u +%Y-%m-%dT%H:%M:%SZ)" \
+  --arg snap_label "$label" \
+  --arg repo "$ROOT_DIR" \
+  --arg head "$head" \
+  --argjson changed_files "$changed_json" \
+  '{timestamp:$timestamp,label:$snap_label,repo:$repo,head:$head,changed_files:$changed_files}' \
+  > "$out"
+
+echo "[snapshot] created: $out"
+if [[ -d "$ROOT_DIR/.git" ]]; then
+  git -C "$ROOT_DIR" status --short --untracked-files=normal
+fi