Add README screenshots: staged in-game captures between description and Downloads

- New capture tool src/test/capture_screenshots.gd (windowed, staged:
  venue overview, targeting an NPC, access inspection, radio report)
- Generated shots saved to docs/screenshots/ and embedded as a 2x2 gallery
  in README above the Downloads section

MEMORY.md

@@ -25,7 +25,7 @@ Session memory for durable decisions, state, and gotchas. Keep concise, remove o
 - Newly added: LATE shift phase (start 700s) with a reachability test; PROTESTER archetype + events + colors; CALL_SOMEONE reaction; `DoorState` core class + `L` binding + visual indicator; flashlight (`G`, SpotLight3D, perception bonus at evening/late); persistence wired (`Save.save_shift_result` on shift end, history + best score on the review screen); `NavigationRegion3D` flat navmesh + `NavigationAgent3D` NPC paths (steps now visual-only); strings moved to `res://content/strings.en.json` (41 keys, loader keeps `lookup`/`fmt`); `export_presets.cfg` (Linux/Windows/macOS) + `tools/build_releases.sh` + `docs/RELEASING.md`; README Downloads section.
 - Run tests: `godot --headless --path . --script res://src/test/test_runner.gd`
 - Boot check: `godot --headless --path . --quit-after 120`
-- Screenshot tool: `godot --path . --script res://src/test/take_screenshot.gd` (writes to `user://screenshot.png`).
+- Screenshot tools: `godot --path . -s res://src/test/take_screenshot.gd` (single shot to `user://screenshot.png`); `godot --path . -s res://src/test/capture_screenshots.gd` (staged README gallery shots to `user://screenshots/`, copied to `docs/screenshots/`).
 - Release build verified locally: export templates for 4.3 installed at `~/.local/share/godot/export_templates/4.3.stable/`; `./tools/build_releases.sh` produced Linux/Windows/macOS artifacts for 0.1.0 in `build/` and the Linux binary passed a headless smoke test. Publishing to Gitea still needs a token (see `tools/publish_release.sh`, `docs/RELEASING.md`).
 
 ## Known Issues / Notes