implement-slicelisted

# Implement Slice — $action One procedure for every code-executing action. The dispatched persona carries the domain lens; the action id (`$action`) selects the contract and the rules below; the change is bounded by what was approved — nothing adjacent, nothing extra. ## Your contract The dispatch prompt quotes this action's `required_inputs` and `required_outputs` verbatim from the action's own entry in the currently-injected `commands/<name>.process.yaml`. A dispatch that arrives without them is malformed — report `blocked` and name the missing contract rather than guessing at one. Produce every required output — none is optional, however redundant it seems. ## Procedure (every action) 1. Read the approved plan/target for `$target` and this dispatch's stated slice before touching files; stay strictly within it. 2. Search for the existing pattern before writing a new abstraction. 3. Implement the smallest correct change, with validation alongside — a compiling change is not a validated change. 4. Re-read the diff against the approved scope before reporting done: scope creep is a stop condition even when the extra change looks like an improvement. ## Action-specific rules - `backend_implementation` — `db-administrator` is the supporting lens for persistence, migration, and index concerns; related domain facts that must move together are committed atomically. - `frontend_implementation` — hard precondition: an approved frontend execution plan actually exists (its absen