Fetch assets from SI files via HTTP Range requests

Replace static animation, texture, and globe bitmap files with a
manifest-driven approach that extracts them directly from the game's
SI files at runtime using HTTP Range requests.

A new generate-manifest script scans SI files by MxCh objectId to
locate each asset's byte offset(s), verifies integrity via MD5, and
writes an asset-ranges.json manifest. The app consumes this manifest
to fetch assets on demand, including support for files split across
MxCh interleave boundaries.

Also removes unused constants (ActorLODIndex, animation keyframe
flag constants).

.gitignore

@@ -4,3 +4,4 @@ isle.wasm
 isle.wasm.map
 isle.js
 LEGO
+asset-ranges.json

package.json

@@ -4,11 +4,12 @@
   "type": "module",
   "scripts": {
     "dev": "vite",
-    "build": "vite build && cp isle.js isle.wasm dist/ && node scripts/workbox-inject.js",
+    "build": "vite build && cp isle.js isle.wasm asset-ranges.json dist/ && node scripts/workbox-inject.js",
     "build:ci": "vite build && node scripts/workbox-inject.js",
     "check": "svelte-check --fail-on-warnings",
     "preview": "vite preview",
-    "prepare:assets": "node scripts/prepare.js"
+    "prepare:assets": "node scripts/prepare.js",
+    "generate:manifest": "node scripts/generate-manifest.js"
   },
   "dependencies": {
     "@floating-ui/dom": "^1.7.5",