Blocking CHANGELOG-at-release enforcement (promotion gate)

[misnaej]

Follow-up to #52 (v1.23.2), which added a non-blocking advisory: forge-next-prep --promotion-status prints a ⚠️ when a pending minor lacks a ## vX.Y.0 entry in origin/dev's CHANGELOG.

This issue tracks the blocking variant — making a missing entry actually fail promotion (e.g. a changelog_entry pre-commit step on release/* branches, or a non-zero exit from a new --require-changelog flag).

Why separate / why MINOR: a new gate is a backward-incompatible behavior change for consumers (a new way for their pipeline to fail) → MINOR per CLAUDE.md semver policy. The advisory shipped as a patch; the gate needs a minor.

Spec: docs/release-process.md §5 (CHANGELOG at release) — currently documents the advisory; promote to a hard rule when this lands.

Requires: a decision on the gate surface (pre-commit step vs CLI flag) and which branches it fires on.

[misnaej]

Closing — superseded by a deliberate design decision, not unfinished work. docs/release-process.md §5 states the chosen enforcement is a non-blocking advisory (forge-next-prep --promotion-status warns when a pending minor lacks its ## vX.Y.0 entry), and in #52 the maintainer explicitly chose non-blocking over the blocking gate. Building #53 would reverse §5, not complete it — and there's no evidence it's needed (the v1.24.0 promotion authored its entry on dev; the advisory correctly stayed silent). YAGNI. Reopen only if the advisory proves insufficient in practice. [issue-triage]