docs: add changelog entry for #452

[Nife-tanny]

Summary

Adds the changelog entry for #452 documenting the AutoPaused stuck-state bug.

The underlying contract fix is already present on main, so this follow-up PR intentionally contains only the missing changelog documentation.

Changes

• Added the [Bug] resume_campaign requires active campaign to clear global AutoPaused — contract can get permanently stuck #452 bug-fix entry to CHANGELOG.md
• No contract logic changes
• No test changes
• No unrelated files modified

Closes #452

[davidmaronio]

the entry is accurate, but the #436 line directly above already documents this exact behavior ("unpause() also clears AutoPaused alongside Paused so neither flag can permanently lock the contract"). two entries for one fix will confuse readers. please drop the new paragraph and instead append #452 to the existing #436 entry, e.g. "(#436, #452)". then this is good to go.

[davidmaronio]

this is still a second paragraph saying the same thing the #436 entry above it already says. please fold the #452 reference into that existing bullet, e.g. append (#436, #452) or extend its last sentence, and drop the new paragraph.