fix: convert cf-kv and excalidraw-libraries from submodules to regular files

- Remove stale cloudflare-worker submodule entry from .gitmodules
- Remove .git dirs from cf-kv and excalidraw-libraries so Git tracks them as regular files
- Fixes 'No url found for submodule path cf-kv' CI error

excalidraw-libraries/package.json

@@ -0,0 +1,16 @@
+{
+  "dependencies": {
+    "@excalidraw/prettier-config": "1.0.2",
+    "http-server": "^14.1.0",
+    "node-static": "0.7.11",
+    "prettier": "2.5.1"
+  },
+  "license": "MIT",
+  "prettier": "@excalidraw/prettier-config",
+  "scripts": {
+    "start": "node index.js",
+    "dev": "http-server .",
+    "build": "prettier . --write",
+    "validate:libraries": "node ./scripts/validate-libraries.js"
+  }
+}