Documents why the markdown/decisions readers load from a retained per-reader nav-history (grab-current-on-mount + single 'load' path) rather than per-view state (dies with the widget — the T-196 bug) or MessageBus retention (wrong layer). The user chose the nav-history helper over a bus fix. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>