Deepgrain Foundry: move from a claude.ai artifact to a local repository

The game as of artifact version 24, ready for local development with
coding agents.

- Source split from three large files into 52 small ones under src/sim,
  src/render and src/ui, joined in the order in src/manifest.json by
  build.py. The joined code is unchanged apart from comments; every
  headless suite gives the same output, and screenshots in both looks
  are pixel-identical to before.
- Light tidying with no change in behaviour: one movement scan loop,
  shared hazard-stripe and belt shader helpers, unused code removed, a
  shared check helper for the test suites.
- World files can be exported as an ordinary download outside claude.ai.
- Tests: broken old scripts removed, experiments moved to tools/,
  test/run_all.py added. Tools: shot.py (repeatable screenshots),
  where.py, map.py.
- Docs: AGENTS.md, CLAUDE.md, NOTES.md (the owner's to-do inbox),
  docs/PROJECT_MAP.md, DESIGN.md, TESTING.md, systems notes, the
  owner's requests and an agent log.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01K9kLmYADKSEjuwUN3rFxDA

src/manifest.json

@@ -0,0 +1,62 @@
+{
+  "shell": "shell.html",
+  "css": [
+    "styles/style.css"
+  ],
+  "sim": [
+    "sim/base.js",
+    "sim/materials.js",
+    "sim/pieces.js",
+    "sim/economy.js",
+    "sim/progress.js",
+    "sim/world.js",
+    "sim/cells.js",
+    "sim/heat.js",
+    "sim/machines.js",
+    "sim/processors.js",
+    "sim/pipes.js",
+    "sim/machine-tick.js",
+    "sim/conveyors.js",
+    "sim/blocks.js",
+    "sim/molds.js",
+    "sim/items.js",
+    "sim/tools.js",
+    "sim/drill.js",
+    "sim/nature.js",
+    "sim/vacuum.js",
+    "sim/actions.js",
+    "sim/blueprints.js",
+    "sim/undo.js",
+    "sim/bot.js",
+    "sim/ledger.js",
+    "sim/weather.js",
+    "sim/tick.js",
+    "sim/worldgen.js",
+    "sim/save.js"
+  ],
+  "client": [
+    "render/setup.js",
+    "render/light.js",
+    "render/world.js",
+    "render/machines.js",
+    "render/overlays.js",
+    "render/smooth.js",
+    "ui/audio.js",
+    "ui/state.js",
+    "ui/title.js",
+    "ui/saves.js",
+    "ui/session.js",
+    "ui/settings.js",
+    "ui/notebook.js",
+    "ui/hud.js",
+    "ui/build-menu.js",
+    "ui/selection.js",
+    "ui/info.js",
+    "ui/input.js",
+    "ui/actions.js",
+    "ui/gamepad.js",
+    "ui/previews.js",
+    "ui/events.js",
+    "ui/loop.js"
+  ]
+}