docs(types): point the spec-side any pin at its upstream issue

The three symbols the ledger cannot burn down — NavigationItem, JoinNode,
FormField — are blocked on the spec exporting them as `any`. Filed as
objectstack#4171 (4 of the spec's 2240 exported types), so the inverted pin and
the burn-down instructions name where the fix lives instead of just saying
"upstream".

Comments only; no behaviour change.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Rvv6qysks2dRLaGfpTdgEy

Author: claude

packages/types/src/__tests__/spec-derived-unions.test.ts

@@ -149,11 +149,13 @@ const _windowFunctionCovers = null as unknown as SpecWindow satisfies WindowFunc
  *
  * `NavigationItem`, `JoinNode` and `FormField` collide with a spec export whose
  * own declaration resolves to `any` (the spec annotates the recursive schemas
- * behind them as `z.ZodType<any>`). Binding objectui's local interface to the
- * spec would replace a precise, documented shape with `any` — a type-safety
- * regression wearing a burn-down's clothes. So they stay in the ledger with
- * their local declarations intact, which is the right answer for as long as the
- * spec cannot describe them.
+ * behind them as `z.ZodType<any>`, and `z.infer` of that is `any`). Binding
+ * objectui's local interface to the spec would replace a precise, documented
+ * shape with `any` — a type-safety regression wearing a burn-down's clothes. So
+ * they stay in the ledger with their local declarations intact, which is the
+ * right answer for as long as the spec cannot describe them.
+ *
+ * Filed upstream as objectstack#4171 (4 of the spec's 2240 exported types).
  *
  * Mutual assignability CANNOT distinguish this case on its own: `any` answers
  * every `extends` question affirmatively, so a naive probe reports these three

scripts/check-spec-symbol-derivation.mjs

@@ -113,7 +113,9 @@ const ALLOW = {
 //   2. The SPEC export resolves to `any` (`NavigationItem`, `JoinNode`,
 //      `FormField`). Re-exporting these REPLACES a precise local interface with
 //      `any` — a type-safety regression wearing a burn-down's clothes. These
-//      cannot be burned down here at all; the fix belongs upstream in the spec.
+//      cannot be burned down here at all; the fix belongs upstream in the spec,
+//      filed as objectstack#4171. `spec-derived-unions.test.ts` carries an
+//      inverted pin that fails the day the spec types one of them properly.
 //      Detect: the same `0 extends (1 & Spec)` probe.
 //   3. The local declaration carries `[key: string]: any` (`FormField`,
 //      `AppSchema`, `PageSchema`, `ThemeSchema`, …) — the objectstack#4075