refactor: Update JSON parsing and schema inflation

- Use `json2.decode[json2.Any]` instead of `json2.raw_decode`
- Add `@[required]` to procedure function signatures
- Improve error handling for missing JSONRPC fields
- Update `encode` to use `prettify: true`
- Add checks for missing schema and content descriptor references

examples/hero/heromodels/heroserver_example.vsh

@@ -1,7 +1,6 @@
 #!/usr/bin/env -S v -n -w -gc none -cc tcc -d use_openssl -enable-globals -no-skip-unused run
 
 import incubaid.herolib.hero.heromodels
-import incubaid.herolib.hero.db
 import time
 
 fn main() {