[BIM] Support parallel loops in BIM and revise iteration-dependent loop policies #14

Overview

Extend the BIM (Binding Instance Model) workflow specification to support parallel loop constructs, and review QoS aggregation and evaluation policies that vary across loop iterations.

Objectives & Scope

• Update BIM schemas and intermediate representations (IR) to define parallel loop semantics.
• Review and refine QoS aggregation policies for loops (handling varying candidate behaviors per iteration vs. constant aggregations).
• Ensure solvers and validation layers correctly lower and interpret parallel loop workflows.
• Add test instances and benchmark cases covering parallel and iteration-dependent loop scenarios.

Acceptance Criteria

• BIM schemas define valid syntax and semantics for parallel loop execution.
• Loop aggregation policies account for iteration-dependent behavior correctly.
• Lowering layer converts parallel loops into valid solver-compatible constraint formulations.
• Unit and integration tests validate parsing, validation, and execution of parallel loop instances.