# TaskRunner Loop and Conditional Step Kinds

## Module
TaskRunner

## Status
IMPLEMENTED

## Description
Extended TaskRunner execution engine with loop and conditional step types, enabling iterative and branching task execution patterns beyond simple sequential flows.

## Implementation Details
- **Step state machine**: `src/TaskRunner/StellaOps.TaskRunner/StellaOps.TaskRunner.Core/Execution/PackRunStepStateMachine.cs` -- manages step state transitions including loop and conditional steps
- **Execution graph**: `src/TaskRunner/StellaOps.TaskRunner/StellaOps.TaskRunner.Core/Execution/PackRunExecutionGraph.cs` -- DAG supports loop and conditional edges
- **Graph builder**: `src/TaskRunner/StellaOps.TaskRunner/StellaOps.TaskRunner.Core/Execution/PackRunExecutionGraphBuilder.cs` -- builds graphs with loop/conditional nodes
- **Expressions**: `src/TaskRunner/StellaOps.TaskRunner/StellaOps.TaskRunner.Core/Expressions/TaskPackExpressions.cs` -- expression evaluation for conditional branching
- **Manifest model**: `src/TaskRunner/StellaOps.TaskRunner/StellaOps.TaskRunner.Core/TaskPacks/TaskPackManifest.cs` -- manifest supports loop and conditional step kind definitions
- **Processor**: `src/TaskRunner/StellaOps.TaskRunner/StellaOps.TaskRunner.Core/Execution/PackRunProcessor.cs` -- processes loop iterations and conditional branches
- **Tests**: `src/TaskRunner/StellaOps.TaskRunner/StellaOps.TaskRunner.Tests/PackRunStepStateMachineTests.cs`, `PackRunExecutionGraphBuilderTests.cs`, `PackRunProcessorTests.cs`
- **Source**: SPRINT_0157_0001_0001_taskrunner_i.md

## E2E Test Plan
- [ ] Verify loop steps iterate the configured number of times
- [ ] Test conditional steps branch based on expression evaluation
- [ ] Verify loop step supports early exit on condition
- [ ] Test nested loops and conditionals execute correctly
- [ ] Verify execution graph handles loop back-edges without cycles