chore(engine): changeset for the declared repository return shapes

Graded `patch`: nothing is widened and no symbol is added. The contract already
published these shapes; the implementation is coming back to a declaration it had
already published. Checked against the recorded WHICH LEVEL ruling of 2026-09-04
(decision batch #35, on #15294), whose `minor` trigger is additive widening.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XTBcV7zZHmokdyQgXjbyEU

Author: claude

.changeset/objectql-scoped-repository-declared-returns.md

@@ -0,0 +1,39 @@
+---
+"@objectstack/objectql": patch
+---
+
+fix(engine): `ObjectRepository` declares the `findOne` / `update` shapes it already published (#16786)
+
+`ObjectRepository.findOne` and `.update` declared `Promise<any>` and now declare
+what `IScopedObjectRepository` — the contract this class carries an `implements`
+clause for — has declared since #16231's ruling A landed (PR #16783):
+
+- `findOne` → `Promise<Record<string, any> | null>`
+- `update` → `Promise<Record<string, any> | number | null>`
+
+**Why this is a `patch` and not a `minor`.** Nothing is widened and no symbol is
+added. `packages/spec/src/contracts/scoped-context.ts` already publishes the
+narrower type, and `IDataEngine` — the call each of these two methods forwards to,
+one line down — already publishes it too. This class sat between two narrow
+declarations and re-widened the result back to `any` on the way out. `implements`
+does not catch that, because a WIDER declared return always satisfies a narrower
+one: `class ObjectRepository implements IScopedObjectRepository` compiled green
+the whole time while the members it published were `any`. So this is an
+implementation coming back to the declaration it had already published — the
+repo's `patch` rung — and not a contract that moved. The recorded **WHICH LEVEL**
+maintainer ruling of 2026-09-04 (decision batch #35, on #15294, recorded at
+`.github/workflows/pr-automation.yml`) puts *additive widening* of a published
+surface — a new exported symbol, a new accepted key or value — at `minor`; this
+PR does none of those, and adds no exported symbol.
+
+**Who has to change something, on the TYPE axis.** A TypeScript consumer that
+typed against the concrete `ObjectRepository` / `ScopedContext` class — rather
+than the `IScopedObjectRepository` contract, which already said this — and reads
+a field off `findOne`'s result without a null check, or off `update`'s result
+without separating the by-id record from the predicate-form count. Those call
+sites were reading `any`; they now read the declared shape and the compiler asks
+for the null check. Consumers already written against the contract, including
+every hook whose `ctx` is typed `HookContext` (`HookContext.api` has been
+`IScopedContext` since #5945), see no change: they were already narrow.
+
+The in-repo census for this change was one file, repaired here.