chore(changeset): regrade to patch, Clause-② no

The seat ruled arm B on the push-back: the measurement governs. Published
behaviour does not move by one row — 0 of 43 ObjectSchema top-level key
verdicts change, the derived refusal set is identical, and no export is added
or removed — so `yes` was over-declared and the bump is a patch.

Claude-Session: https://claude.ai/code/session_01AmH9bKvGoLjiY86Q4Z3og2
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude

.changeset/19150-declares-collection-pipe-authorable-side.md

@@ -1,10 +1,10 @@
 ---
-'@objectstack/spec': minor
+'@objectstack/spec': patch
 ---
 
 fix(spec): `declaresCollection` reads a `pipe` on the side the author writes, so a `z.preprocess`-wrapped collection key cannot silently leave the `objectConflict: 'merge'` refusal set (#19150)
 
-Clause-②: yes
+Clause-②: no
 
 `objectCollectionKeys()` derives — never transcribes — the object-level keys `composeStacks({ objectConflict: 'merge' })` refuses to combine (#14848), and the reason it derives them is written into its own docblock: a hand-written list "would fail in the silent direction: a collection key added to the object schema tomorrow would fall back to the wholesale replacement this rule exists to refuse". The walker behind it reintroduced exactly that silent direction through the derivation itself.