Design.BoundaryFrozen

Stub-warns when a source file lives inside a boundary marked frozen = true in cofferdam.invariants.toml. The intent is to make a frozen architectural area visible during code review without blocking work.

Configuration

[boundaries]
"src/legacy/**" = { frozen = true, reason = "see ADR-0007" }

When frozen = true, every source file matching the glob receives one finding from this check, with the configured reason echoed in the message. v0 does not yet distinguish new additions to the area from existing files — every match emits. Per-file deltas against a baseline are tracked under a follow-up bead.

Suppression

Use a normal severity override or the inline // cofferdam-disable-next-line suppression directive when the area is intentionally still active during migration work.

Rationale

A frozen boundary is an architectural intent: "no new code here". v0 surfaces the intent; v1 will turn intent into enforcement using the baseline machinery already used by cofferdam check --baseline.