docs(agent): #116 undercounted the phantom reads, and two of them are live bugs

Re-grepped the tree instead of trusting eb38008's own account of it. Two
corrections, both in the direction of worse:

A fourth read: services.nix:80 `printing.enable`. The original enumeration
only looked at options.nix, which is the same mistake in miniature as the
bug it was filing — `or` hides a dead bridge, so the only honest check is a
grep of all of modules/nixos/, which the item's own pass condition already
said and its own list did not do.

"Benign today" was wrong about Bluetooth. The TUI control center is shipped
(default.nix:337) and reachable from the menu's Control Center row, and its
Bluetooth and Printing toggles write settings.bluetooth.enable /
settings.printing.enable and print "disabled (requires rebuild)". Nothing
reads either key, so the fallback wins and the rebuild changes nothing. Two
user-facing toggles that report success and do nothing — that is a live bug,
not a dead key. batteryChargeLimit stays benign for the stated reason: its
menu patches the baked option instead.

nomarchy.settings is declared in exactly one place, modules/home/options.nix:
412 — verified, not assumed. V0: nix flake check --no-build passes.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

agent/BACKLOG.md

@@ -123,30 +123,46 @@ a suspended machine hibernates after the configured delay and resumes, and a
 machine without hibernate support hides the row instead of offering a
 suspend that never wakes.
 
-### 116. Three NixOS options read a `config.nomarchy.settings` that does not exist
+### 116. Four NixOS options read a `config.nomarchy.settings` that does not exist — two are live broken toggles
 
-Found while wiring System › Auto-login (2026-07-14). `nomarchy.settings` is
+Found while wiring System › Auto-login (2026-07-14); **enumeration corrected
-declared and populated **only on the Home Manager side** (`modules/home/
+2026-07-14** — the original said "three options … benign today", and both
-options.nix`, filled by `theme.nix`). On the NixOS side the attribute is
+halves were wrong (see the Bluetooth/Printing rows).
-absent, and `or <fallback>` swallows the missing-attribute error — so these
-defaults have silently always been their fallback on every machine:
 
-- `nomarchy.system.greeter.autoLogin` — **fixed in this commit** (now reads
+`nomarchy.settings` is declared in exactly ONE place —
-  the state via `theme-state-read.nix` in `greeter.nix`, the working pattern
+`modules/home/options.nix:412`, the Home Manager side, filled by `theme.nix`.
-  from `hardware.nix`/`timezone.nix`). Left here as the worked example.
+On the NixOS side the attribute does not exist at all, and `or <fallback>`
-- `modules/nixos/options.nix` `bluetooth.enable` — `settings.bluetooth.enable`
+swallows the missing-attribute error, so every read below has silently always
-  never read; benign today (fallback `true` = the intended default) but the
+been its fallback on every machine ever built:
-  state key is dead.
-- `modules/nixos/options.nix` `power.batteryChargeLimit` — `settings.power.
-  batteryChargeLimit` never read; the Battery limit menu works because it
-  patches the baked option in `system.nix` instead, which is the older model.
 
-Decide per option whether the state key should work (wire it like the
+- `modules/nixos/greeter.nix` `system.greeter.autoLogin` — **fixed** in
-greeter) or the phantom read should just go. The trap is that `or` makes both
+  eb38008 (reads the state via `theme-state-read.nix`, the working pattern
-a live bridge and a dead one look identical — a grep for
+  from `hardware.nix`/`timezone.nix`). The worked example; copy this shape.
-`config.nomarchy.settings` under `modules/nixos/` should return nothing when
+- `modules/nixos/options.nix` `bluetooth.enable` — **live bug, not benign.**
-this is done. Pass = no NixOS option claims a state default it cannot read,
+  The TUI control center (`nomarchy-control-center.sh:192`, shipped in
-and any bridge kept is proved by an eval that flips with the state file.
+  `modules/nixos/default.nix:337`, reachable from the rofi menu's "Control
+  Center" row) has a Bluetooth toggle that writes `settings.bluetooth.enable`
+  and prints "Bluetooth disabled (requires rebuild)". Nothing reads that key,
+  so the fallback `true` wins and Bluetooth is still on after the rebuild.
+  The toggle reports success and does nothing.
+- `modules/nixos/services.nix:80` `printing.enable` — **live bug, same shape**
+  (`nomarchy-control-center.sh:203`). Missed by the original enumeration
+  entirely, which only looked at `options.nix`.
+- `modules/nixos/options.nix:112` `power.batteryChargeLimit` — never read, but
+  the Battery limit menu works anyway because it patches the baked option in
+  `system.nix` instead (`modules/home/rofi.nix:342`), the older model. Dead
+  read, working feature.
+
+Decide per option whether the state key should work (wire it like the greeter)
+or the phantom read should just go — but the two control-center toggles need
+one or the other, since today they lie to the user. The trap is that `or`
+makes a live bridge and a dead one look identical, which is exactly how the
+first pass undercounted: **grep the whole of `modules/nixos/`, not
+`options.nix`.** Pass = `grep -rn 'config\.nomarchy\.settings' modules/nixos/`
+returns nothing but comments, no NixOS option claims a state default it cannot
+read, any bridge kept is proved by an eval that flips with the state file, and
+the control-center Bluetooth/Printing toggles are proved to actually change
+the built config (or are removed).
 
 ### 107. Rename `theme.json` to reflect that it is the system state