implementation-discoverylisted

# Implementation Discovery (internal) The one authoritative owner of the bounded, read-only pre-write mapper consumed by `execute-phase`. A phase does not touch the repository until this step has closed its questions and said `READY`. Nothing else may define what a valid pre-write discovery pass is. ## When to use - `execute-phase` — before any branch/planning/source write, after the read-only dependency/status/acceptance/phase/feature-28 receipt checks. - The step runs only on the pre-write route; it is never a general-purpose orientation pass and never a substitute for planning. ## Inputs (exact, only these) The mapper receives only: - the governing SPEC/fix obligations for the current phase; - the current feature-28 SPEC and Plan receipt digests; - the phase-relevant rows from frozen planning evidence, with source revision, affected decision/obligation, freshness, and declared unknowns; - the phase fingerprint, ordered tasks, acceptance/obligation ids, and the last progress receipt; - source HEAD plus clean-source / allowed-planning-path evidence; - applicable NRS / decision / invariant evidence; - the repository discovery tools available in this environment. ## Advisory locators Semantic/symbol navigation and Engram/memory tools are optional adapters that may locate evidence faster; they are never authority. Direct repository/Git/search/ read/test fallback must satisfy the identical evidence contract, and only repository bytes answer a map field. The tool