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/x.mjs

@@ -0,0 +1,5 @@
+import { readFile } from "fs/promises";
+
+const lib = await JSON.parse(await readFile("./libraries.json"));
+
+console.log(Object.values(lib).length);