Declarative TOML-based MIG-tree <-> BO4E mapping engine.

Architecture

• TOML mapping files define simple 1:1 field mappings
• Complex handlers are Rust functions for non-trivial logic
• MappingEngine loads all definitions and provides bidirectional conversion

Usage

let engine = MappingEngine::load("mappings/FV2504/UTILMD_Strom/pid_55001")?;
let def = engine.definition_for_entity("Marktlokation").unwrap();
let bo4e = engine.map_forward(&tree, def, 0);
let instance = engine.map_reverse(&bo4e, def);