Implement TODO backlog: LATE phase fix, protester, CALL_SOMEONE, door lock, flashlight, persistence, navmesh, JSON localization, and release tooling

- Fix LATE shift phase (start 700s) so the violent-threat event is reachable
- Add PROTESTER archetype (rules, profile, colors, events in public venues)
- Add CALL_SOMEONE reaction (FSM -> ARGUING, influencer/trespasser/protester weights)
- Door lock: DoorState core class, L binding, red/green visual indicator,
  locked doors thwart FORCE_ENTRY
- Flashlight: G binding, SpotLight3D, perception radius bonus at evening/late
- Persistence: save shift results via Save autoload, history + best score on
  review screen, round-trip test
- Navigation: flat NavigationRegion3D navmesh, NavigationAgent3D path following
  with direct-movement fallback; steps made visual-only so NPCs reach entrance
- Localization: strings moved to content/strings.en.json (loader keeps
  lookup/fmt signatures; coverage test over all keys)
- Distribution: export_presets.cfg (Linux/Windows/macOS), tools/build_releases.sh,
  docs/RELEASING.md, prominent README Downloads section
- Remove stale signal_bus.gd (invalid static-signal experiment)
- Tests: 53 passing across 9 suites

tools/build_releases.sh

@@ -0,0 +1,34 @@
+#!/usr/bin/env bash
+# Build distributable desktop executables with the Godot export pipeline.
+#
+# Requirements:
+#   - Godot 4.3 (or the version in project.godot `config/features`) on PATH,
+#     with export templates installed (see docs/RELEASING.md).
+#   - Run from the repository root.
+#
+# Produces:
+#   build/step-line-linux-<version>.x86_64
+#   build/step-line-windows-<version>.exe
+#   build/step-line-macos-<version>.zip
+#
+set -euo pipefail
+
+GODOT="${GODOT:-godot}"
+VERSION="$(grep -oP 'config/version="\K[^"]+' project.godot)"
+mkdir -p build
+
+echo "==> Exporting Linux (x86_64)"
+"$GODOT" --headless --export-release "Linux" "build/step-line-linux-${VERSION}.x86_64"
+
+echo "==> Exporting Windows Desktop"
+"$GODOT" --headless --export-release "Windows Desktop" "build/step-line-windows-${VERSION}.exe"
+
+echo "==> Exporting macOS"
+"$GODOT" --headless --export-release "macOS" "build/step-line-macos-${VERSION}.zip"
+
+echo ""
+echo "Artifacts:"
+ls -la build/*"${VERSION}"*
+echo ""
+echo "Upload to: https://git.allucanget.biz/zwitschi/security-game/releases"
+echo "See docs/RELEASING.md for the full release checklist."