ADR-0104 — Ephemeral by default: gitignore the working set, commit only durable truth

Context

Flow artifacts — intake, task, review — accumulate one set per change; most are read once and never again. Committed (ADR-0060) and aged-out by convention (ADR-0096), they depend on discipline that drifts at scale, so the live tree bloats into an unread landfill. ADR-0103 moved the durable evidence into the spec's ## Execution and lessons into findings/ — so the flow artifacts no longer hold the record; they are working state. Ratified from RFC-ephemeral-default (suspec-works#73).

Decision

1. Gitignore the working set; commit only durable truth. The test: will it be re-read by future work? Durable (committed): the spec (contract + ## Execution), findings/, decisions/ + ADRs, and the board (status.md). Ephemeral (gitignored): intake/, tasks/, reviews/, suspec check output, run logs, agent scratch. Noise never committed cannot accumulate — the structural guarantee a convention can't give. Level: convention (the gitignore is the enforcement).

2. Reviews are configurable. Ephemeral by default; a documented opt-in keeps reviews/ committed (and aged out) for audit/regulated teams that need the standing independent-verification trail. Level: convention.

3. Topology-agnostic. This is a per-artifact-class decision, independent of where the workspace lives (the topology question is parked separately).

Consequences

• Reverses ADR-0060's commit-the-flow-artifacts decision — re-adopting the spirit of ADR-0004 (gitignored flow artifacts), now earned by ADR-0103 putting the evidence in the spec. Amends ADR-0096: the ephemeral classes are gitignored, not commit-then-age-out.
• The audit-trail subtraction (gitignored reviews) is named and accepted, mitigated by the configurable opt-in; post-ADR-0103 the spec's Execution + findings + the PR carry most of the record.
• Implementation deferred (later plan): the kit .gitignore.additions gains the ephemeral classes; docs/03-where-files-live / 02-basic-workflow / ADOPTING describe the partition. No change ships with this ADR (decision only).

Affected obligations / constraints

• Reverses: ADR-0060 (committed flow artifacts). Amends: ADR-0096 (lifecycle). Builds on: ADR-0103 (evidence in the spec).
• Does NOT change: the durable artifacts (spec/findings/decisions/board stay committed), the verdict model, or the checks contract.