Build: Stop tracking changelog-proposals.edn run scaffolding

The merge_proposals.clj spine writes its proposal queue to the repo
root instead of under the gitignored .local/runs/ tree, so it leaked
into the audit branch and collided on rebase. Untrack it and ignore
the path; the file is working-state run scaffolding, not source.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: leifericf

.gitignore

@@ -104,3 +104,6 @@ embed_api_test
 crash_handler_test
 dist/
 dist-cross/
+
+# Audit/review run scaffolding written to repo root by merge_proposals.clj
+changelog-proposals.edn