Ln 520 Test Planner

Orchestrates the three-phase test planning pipeline after a story's implementation is done: research via ln-521, manual testing via ln-522, and automated test planning via ln-523. Each worker runs in isolation with its own runtime tracking and writes structured summaries that the coordinator consumes. You can skip straight to automated planning with the simplified flag if you're in fast-track mode. The runtime contract is detailed and deterministic, designed for resumable execution with clear phase gates. It's an L2 coordinator that delegates everything and does no direct work itself. Use it when implementation tasks are done, regression passed, and you need complete test coverage planning before marking a story finished.