docs(changelog): Unreleased entry for the PREGATE_NO_LANE own-policy line and the pr-body duplicate refusal

Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>

CHANGELOG.md

@@ -1,5 +1,24 @@
 # Changelog
 
+## [Unreleased]
+
+**A branch that adds its own pregate lane now learns why it still fails, and `gstack-post pr-body` no longer keeps a stale copy of a section.** Pregate reads its policy from the base branch so a branch cannot loosen its own gate. A branch that had already declared a lane in its own `.gstack/pregate.json` was still told to declare it, and went round in a circle. Separately, a PR body that held `## What changed` twice (an old description pasted under the /ship body) kept the old copy every time /ship reposted.
+
+### Fixed
+- **`PREGATE_NO_LANE`**: when the branch edits `.gstack/pregate.json` and the policy comes from the base copy or the user-owned file, the fix line names that policy, says a lane the branch adds counts only once it is on the base, and offers both routes: land the policy change in its own PR first, or rerun with `--policy-from head --allow-repo-commands`, which records the run as unreviewed. Pregate still never reads the branch's policy on its own. (#3574)
+- **`gstack-post pr-body`**: when the PR's current body holds a title from the file more than once, it posts nothing, exits 64 and says to rerun with `--replace` and the whole body. /ship's PR-body step stops on that refusal and reports the duplicated titles instead of reposting with `--replace` itself, since a person chooses which copy stays. (#3575)
+
+### Docs
+- `docs/troubleshooting.md#pregate-no-lane-own-policy` explains the own-policy case and its two routes; `docs/pregate.md`'s trust boundary links it. The `gstack-post-pr-body-merge` entry covers the duplicate-title refusal.
+
+### Tests
+- `test/pregate-selection.test.ts`: the own-policy fix line under the base policy; a head-policy run and a branch that deletes `pregate.json` get the plain fix.
+- `test/pregate-user-policy.test.ts`: the own-policy line names the user file as the policy source.
+- `test/gstack-post.test.ts`: a doubled title refuses and posts nothing, `--replace` posts the file, and a body with two receipt blocks refuses too.
+
+### Gate integrity
+- `test/gstack-post.test.ts`: the duplicate-titles assertion that expected the first copy replaced and the second kept now expects the refusal, plus a case where duplicates the file does not touch are still kept.
+
 ## [1.91.304.0] - 2026-10-29
 
 **Running the Capy installer for a second workflow on the same machine no longer takes away the first one's admission.** /ship's docs step runs `scripts/install.sh --for document-release`, and that run replaced the `--for ship` install verdict with its narrower one, so the rest of /ship refused with "the install verdict certified for=document-release, which does not cover codex that ship needs" until someone reran `--for ship` (#3561, seen on gstack-evals#13).