Decide root package ownership and the implicit src/main.rs bin

[metaphorics]

Question

The workspace root is itself a package, bamts-bench (Cargo.toml:1-28, publish = false), with three explicit benchmark/evidence bins (Cargo.toml:11-21):

• jit_benchmarks → bench/jit_benchmarks.rs
• stage0_evidence → bench/stage0_evidence.rs
• stage1_regression_guard → bench/stage1_regression_guard.rs

In addition, an untracked file src/main.rs (?? src/main.rs in git status) is a 19-line ICU calendar probe importing icu::calendar and icu::locale (src/main.rs:1-17). The root [dependencies] declare only bamts-verification and serde_json (Cargo.toml:23-25); nothing provides the icu crate. Because Cargo auto-treats src/main.rs as an implicit bin named bamts-bench, the file currently breaks any command compiling the root package's bins when present; when absent (a CI checkout) the target silently vanishes.

The decision to make is: keep, rename, split, or remove the root package; whether to declare or remove the implicit bin; and the recovery disposition of the untracked file. The research snapshot recorded different bin names (jit_benchmarks, stage_evidence, stage_regression, stage_response_guard) and explicitly warned the surface is moving.

Consumer evidence required

• Every consumer of each explicit bin: workflows, Justfile recipes, runbook commands, and verification/perf ledgers that reference stage0_evidence or stage1_regression_guard outputs. The docs audit in Audit documentation rules and build surfaces #163 and the workspace research (.outline/research/workspace-boundaries.md shallow-adapter table, root package row) are the starting inventory; the ticket must positively identify each caller before any reshape.
• Proof that no documented or scripted path invokes the implicit bamts-bench bin (search docs/, Justfile, .github/, npm/ for --bin bamts-bench or bare cargo run at root).
• Reproduction of the manifest conflict: cargo check -p bamts-bench with the untracked file present and absent (scoped, local).
• Untracked-file provenance: Audit documentation rules and build surfaces #163's resolution records src/main.rs as an unrelated, untracked root file that stays protected until an explicit boundary and recovery decision; that recovery is part of this ticket.

Unresolved boundary channels

• Whether the explicit bench/evidence bins feed release-admission artifacts consumed by Define release admission lifecycle #178; if so, any root reshape must preserve their output identity.
• Whether the workspace root should remain a package at all (removal changes workspace membership from 12 to 11 members and changes cargo metadata target kinds).
• Whether the ICU probe is a retained need (it would become a declared, named, dev-scoped target with its own dependency) or abandoned.

No-go conditions

• Do not delete src/main.rs, and do not delete or rename any explicit evidence bin, from absence-of-consumers alone; absence of local callers is not absence of consumers.
• Do not "fix" the probe by adding icu dependencies to the root manifest as a silent repair; making the implicit bin compile is one possible fork outcome and must be an explicit decision.
• No package/target/membership change without the decision stating its effect on the workspace guard's expected graph (crates/bamts-verification/src/workspace_guard.rs).

Observable acceptance

• Written decision: root package fate (keep / rename / split / remove) and implicit-bin fate (declared target with owner / removed), each justified by the consumer inventory.
• Every explicit bin has a named consumer (workflow / runbook / ledger citation) recorded in the decision, or an explicit approved removal with recovery path.
• Untracked-file disposition recorded (adopted as declared target / recovered to an owner / removed with approval) per Audit documentation rules and build surfaces #163's protection rule; never silently deleted.
• cargo metadata --no-deps target kinds for the root package match the decision exactly.
• The decision names any required workspace-guard graph change to keep the expected graph truthful.

Blocked by

• #159: Map crate dependencies and boundary consumers — produced the root package, binary, and dependency evidence.
• #163: Audit documentation rules and build surfaces — confirmed the untracked status and the rule that the file stays protected until a boundary and recovery decision.
• #169: Design the crate topology and stable facade — determines whether the root package stays a workspace member, is renamed, is split, or is removed.

[metaphorics]

Dependencies

This issue is blocked by:

• Map crate dependencies and boundary consumers #159 — Map crate dependencies and boundary consumers (produced the root package, binary, and dependency evidence)
• Audit documentation rules and build surfaces #163 — Audit documentation rules and build surfaces (confirmed the untracked status and the rule that the file stays protected until a boundary and recovery decision)
• Design the crate topology and stable facade #169 — Design the crate topology and stable facade (determines whether the root package stays a workspace member, is renamed, is split, or is removed)

Parent: #156. Feeds: #185 (root-ownership decision for DRB-7 residue child).