🧩 Implement HM-style type inference

[timfennis]

The analyser currently defaults to StaticType::Any in several places that would require a proper
Hindley-Milner (or similar) type inference system to resolve correctly. These are all tightly
coupled and should be addressed together.

Affected areas

• Function parameter types (ndc_analyser/src/analyser.rs)
  All function parameters default to StaticType::Any. A proper inference pass is needed to
  propagate types from call-sites back to parameter positions.

• None / Option type inference (ndc_analyser/src/analyser.rs)
  None is typed as Option<Any>. HM inference (or mandatory type annotations on the binding
  site) is needed to determine the inner type.

• Empty list type (ndc_analyser/src/analyser.rs)
  [] is typed as List<Any>. Needs type parameters on List plus inference from usage context.

• Empty / partially-typed map (ndc_analyser/src/analyser.rs)
  Map key/value types default to Any when no elements are present. Same issue as empty list.

• For-loop iteration element type (ndc_analyser/src/analyser.rs)
  The element type of a sequence in a for loop falls back to Any. Needs type parameters on
  sequence types (List, Range, etc.) to propagate the element type.

• Binding::Dynamic return type (ndc_analyser/src/analyser.rs)
  When a call resolves to Binding::Dynamic, the analyser returns a Function { return: Any }
  placeholder. With better inference the actual return type could be narrowed.