todo: one file per item, grouped by theme, with a generated index

TODO.md had reached 1050 lines and 72 open items across 28 sections, read mostly
on a phone. It is now a directory: todo/<theme>/<item>.md, one card per file, with
frontmatter carrying id, status, created date and order, and the prose body copied
across verbatim. TODO.md becomes a generated index (bun run todo:index).

Dates: where an item's prose stated one it is used; otherwise its old section's;
otherwise 2026-08-20, floored at the day before the split rather than invented.
date_source records which.

Shaped for a two-way Kanban board, filed as todo/tooling — a card is a file, id is
the identity, frontmatter is the machine's half and the body is the owner's.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

todo/plugin-infrastructure/a-plugin-cannot-run-host-setup.md

@@ -0,0 +1,15 @@
+---
+id: plugin-infrastructure/a-plugin-cannot-run-host-setup
+title: "A plugin cannot run host setup"
+theme: plugin-infrastructure
+status: open
+created: 2026-08-20
+date_source: assumed
+order: 2
+---
+
+**A plugin cannot run host setup.** `osDependencies` installs packages; it cannot reconfigure a
+display manager, and `plugins/desktop/setup/setup-desktop.sh` forces Xorg, enables auto-login and
+needs a reboot. Left manual. The owner recalls a mechanism for this existing months ago and being
+removed — **look in git history before designing a new one**, it reportedly worked and made the
+install page considerably better than it is now.