Resolve format arguments in derive Display

[RAprogramm]

Summary

• add a FormatArgumentsEnv to masterror-derive to cache format arguments, emit prelude bindings, and resolve placeholders before falling back to fields
• extend placeholder helpers to honor the environment for structs and variants, keeping implicit indices in order and preserving previous error diagnostics when no argument matches
• normalize positional indices while parsing format args and add regression tests for implicit, explicit, and mixed placeholder usage

Testing

• cargo +nightly fmt --
• cargo +1.90.0 clippy -- -D warnings
• cargo +1.90.0 build --all-targets
• cargo +1.90.0 test --all
• cargo +1.90.0 doc --no-deps
• cargo audit
• cargo deny check

---

https://chatgpt.com/codex/tasks/task_e_68cde7465378832bb1a1ac5099816cd7