L Lane Master for Light Driven Quantum Switching Under the G–Σ–P–L Contract

This manuscript establishes the L lane as a fully disciplined coordinate layer within the G–Sigma–P–L stack, transforming the ledger from an informal bookkeeping device into a contract-bound, falsifiable decision system. It defines contracts, capsules, observation tokens, and ledgers in a platform-independent manner and enforces that every decision be reproducible from token data alone under fixed guards, with no threshold travel and no hidden state. The work formalizes a three-level falsification hierarchy—replayability, no-threshold-travel, and one-way federation with Four-Solves-Three closure—and extends it with explicitly non-gating metadata and audit mechanisms, including Strong versus Strong-to-Weak tagging and Sum-of-Zeros shadow-ledger analysis. By insisting on immutability, replay, and separation between live certification and long-horizon auditing, the manuscript provides a durable operational blueprint that applies equally to photonic, magnetic, valleytronic, phononic, and Hilbert-style experimental programs, enabling cross-platform comparison and long-term integrity without exposing raw traces or proprietary control logic.