fix(changelog): restore and rewrite reverted cleanup fragment descriptions

- Restore bounded-cleanup-history-replay.md with description of reverted #6388 cleanup features
- Restore verified-cleanup-sdk-recovery.md with description of reverted terminal publication and recovery changes
- Both fragments now accurately describe what was reverted in this PR rather than advertising unshipped features
- Preserve changelog fragment records per release flow requirements (scripts/release.ts)

Author: GJC Multisession

packages/coding-agent/changelog.d/bounded-cleanup-history-replay.md

@@ -1,2 +1,3 @@
-### Fixed
-- Bound existing cleanup-pending history replay before inventory retention and receipt allocation, preserve numeric contiguous attempts and retained-file authority, and forward explicit journal-capacity refusal through SDK saved-session omission diagnostics.
+### Reverted
+
+- The bounded cleanup-pending history replay feature from #6388 has been reverted in this PR. Cleanup behavior reverts to pre-#6388 handling.

packages/coding-agent/changelog.d/verified-cleanup-sdk-recovery.md

@@ -0,0 +1,9 @@
+### Reverted
+
+- The verified SDK recovery and session cleanup contracts from #6388 have been reverted in this PR to address terminal publication edge flakes. The following aspects of #6388 were reverted:
+  - SDK terminal publication and submission completion ownership changes
+  - Verified session cleanup and owner-free deletion handling
+  - Durable terminal recovery coordination
+  - Historical sibling session authentication
+
+Cleanup and task-owner features that newer dev commits depend on were preserved.