chore(changeset): reference-integrity suite entry point (#3583 D5)

The suite adds public API to @objectstack/lint (validateReferenceIntegrity,
REFERENCE_INTEGRITY_RULES and its types), so it releases as a minor there and
a patch on the CLI, whose behaviour is unchanged.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015r31hzuSN19iK8ATRPcCpS

Author: claude

.changeset/lint-reference-integrity-suite.md

@@ -0,0 +1,30 @@
+---
+"@objectstack/lint": minor
+"@objectstack/cli": patch
+---
+
+refactor(lint): one entry point for the reference-integrity suite (#3583 D5)
+
+Six rules that answer the same question — "does this name resolve to anything?"
+— were wired by hand into three CLI commands, so landing a rule meant editing
+`validate`, `lint` and `compile`, and forgetting one meant the same stack got a
+different verdict depending on which command the author ran.
+
+New public API on `@objectstack/lint`:
+
+- `validateReferenceIntegrity(stack)` — runs every reference-integrity rule and
+  returns the concatenated findings.
+- `REFERENCE_INTEGRITY_RULES` — the ordered list behind it (`validateObjectReferences`,
+  `validateActionNameRefs`, `validatePageFieldBindings`, `validateChartBindings`,
+  `validateNavAccess`, `validateTranslationReferences`).
+- `ReferenceIntegrityFinding` / `ReferenceIntegrityRule` / `ReferenceIntegritySeverity`
+  — one finding type instead of a six-way union.
+
+Adding a rule to that list reaches `validate`, `lint` and `compile` with no
+further wiring. The individual rule exports are unchanged, so nothing that
+imports them directly needs to move.
+
+Behaviour-preserving: identical findings on the three example apps (zero) and
+on the HotCRM corpus (24, unchanged per rule). `os doctor` is deliberately not
+converted — it runs only `validateWidgetBindings` and is an environment health
+check rather than an authoring gate.