The Codex installer's `findNextTableHeader` skipped `[[array-of-tables]]` headers instead of treating them as a block boundary, so any `[[...]]` block after `[mcp_servers.codegraph]` in ~/.codex/config.toml was silently deleted on install/upgrade/uninstall. Now treats both `[...]` and `[[...]]` as boundaries, with a small line lexer so header-shaped text inside multiline strings/arrays isn't mistaken for a boundary. Adds round-trip regression coverage (install → reinstall → uninstall) + CHANGELOG entry.
Fixes#1351. Supersedes #624.
Thanks @KtzeAbyss.
