feat(spec-phase): prohibition probe — surface "must-NOT" constraints (#644) (#1149)

Adds the spec-time prohibition probe (spec-phase Step 5.6) — the second adapter of the probe-core resolution model. Surfaces unwritten must-NOT constraints as negative SPEC acceptance criteria with test/judgment verification tiers; fail-closed at verify time. Per ADR-550. Closes #644.

docs/README.md

@@ -19,6 +19,7 @@ Language versions: [English](README.md) · [Português (pt-BR)](pt-BR/README.md)
 - [Install a minimal GSD and add skills later](how-to/install-minimal-and-add-skills.md) — install only the core skills, then grow the surface with profiles and `/gsd:surface`
 - [Discuss a phase](how-to/discuss-a-phase.md) — capture implementation decisions before planning begins
 - [Resolve edge-coverage findings](how-to/resolve-edge-coverage-findings.md) — turn the spec phase's surfaced domain-boundary edges into covered, dismissed, or backstopped spec decisions
+- [Resolve prohibition findings](how-to/resolve-prohibition-findings.md) — turn the spec phase's surfaced must-NOT constraints into resolved, dismissed, or deferred spec decisions
 - [Plan a phase](how-to/plan-a-phase.md) — run research, decompose work, and verify plan quality
 - [Execute a phase](how-to/execute-a-phase.md) — run plans in parallel waves with fresh-context subagents
 - [Verify and ship](how-to/verify-and-ship.md) — walk through completed work, diagnose failures, and create the PR