Clean up code. Reorganize files. Port stuff from other branches. + more

This turns the project into a monorepo using pnpm workspaces,
dramatically simplifying the build process. It also fixes a lot of bugs
and just generally makes the codebase a lot cleaner.

README.md

@@ -14,6 +14,6 @@ This is the impost monorepo, containing the following packages:
 - `@impost/lib`: A library that can be used to generate, solve, and verify
   proofs.
 
-It also contains a `solver` package, which is the PoW solver written in Zig,
-`@impost/lib` is built on top of, an example of how to use the solver in a
-nuxt 3 project.
+It also contains a `solver` package, which is the Zig PoW solver that
+`@impost/lib` is built on top of, an example of how to use the solver in
+example-app