feat: close the business-alignment loop in RPI and Code Review #3184

Issue Description

Business intent in BRDs, PRDs, and ADRs is cited when RPI work is planned, but nothing after planning reads those sources again. When implementation changes direction, the requirement documents and their owners are never told, and Code Review has no way to check a pull request against the business decisions behind it. Over time requirements, decisions, and delivered behavior drift apart.

This work closes that loop without adding a new skill or any automatic outbound action:

• rpi-plan finds, cites, and status-checks BRD, PRD, and ADR sources with a quick bounded search, and always cites the latest copy of a superseded document.
• rpi-implement records Business Alignment entries when work changes or diverges from a cited requirement, and compares completed work against every cited source before review.
• rpi-review gains a shared business-alignment reference that rates drift by business stake (MoSCoW priority of the traced goal, or ADR significance) and owner awareness (unrecorded, developer-confirmed, owner-acknowledged), raises stale-source and source-gap alerts, routes source updates and architecture review follow-ups, and offers a copy-ready note to the source owner.
• The Code Review agent loads the same reference through a Security-Plan-Drift-style extension. It discovers sources from an explicit input, the PR and linked issues, changed business documents, and a quick repository search; compares against the base-branch revision so a PR cannot hide drift or lower its own rating; counts Critical and High alignment findings toward request_changes; and lets only the human reviewer confirm owner acknowledgment.
• ADR 0012 records the decision (status: proposed).

Additional Context

• Acceptance: alignment-affecting changes are captured in RPI changes records; RPI Review and Code Review rate drift with one rubric; no tracker writes, messages, or source-document edits are added; local validation passes.
• Out of scope (follow-ups): carrying business context into tracker work items (ADO, GitHub, Jira) through the Functional Planner and Backlog Manager; model-graded eval checks for the business-alignment stimuli.