Add support for chained API syntax in Wave

[LunaStev]

Background:

Currently, Wave does not support chained function or method calls such as object.method1().method2().
Chained APIs improve readability, especially when dealing with operations that return intermediate values.

Expected Behavior:

Allow multiple method calls or function-style chains in a single expression.
For example:

var text: str = " hello ";
var result: str = text.trim().to_uppercase().slice(0, 3);

• Each call should return a new value or reference to allow the next method in the chain.

• Support both built-in functions and user-defined functions with return values.

User Scenarios:

1. A developer wants to transform a string with multiple operations in a single expression.
2. A library function returns a struct, and the user calls a method on that struct immediately.
3. Improves readability for pipelines such as read().parse().validate().store().

Additional Information:

• Language version: - (not yet assigned)

• Target branch: develop

• This will require changes to the parser and expression evaluator, possibly also type resolution.