feat(menu): #79 slice 3 — Look & Feel › Auto theme (completes #79)

Adds an "Auto theme (on/off)" row to Look & Feel and an `autotheme`
submenu: toggle the feature, pick the day/night themes (from
`nomarchy-theme-sync list`), and set the sunrise/sunset times (HH:MM,
validated). This is the menu surface over settings.autoTheme, completing
the auto time-of-day theme feature (slices: CLI / timer / menu).

Enabling writes the flag and defaults the summer-day/summer-night pair
--no-switch, then runs `auto --force`, so a single rebuild both installs
the timer and applies the correct theme for now. Disabling is instant
(--no-switch): the flag flips and `auto` self-gates, so the lingering
timer no-ops until the next rebuild. Day/night/time writes are live
--no-switch (read by `auto` at tick time).

Verification: V1 — HM generation builds (bash -n on nomarchy-menu at
build) + bash -n on the built menu. Logic test with stubbed
rofi/theme-sync/notify: selecting the toggle from off runs exactly `set
day/night/enable ... --no-switch` then `auto --force` — the intended
one-rebuild path. V0 flake check green. All three #79 slices shipped;
the live timer switch across sunset is a real-session (V3) check on a
Nomarchy machine.

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

agent/BACKLOG.md

@@ -28,28 +28,22 @@ in [`docs/ROADMAP.md`](../docs/ROADMAP.md); map in
 
 ## NEXT
 
-### 79. Auto time-of-day theme pair (`VISION § D`) `[big]` — split
-Auto light/dark theme switch through the **existing** engine (a timer runs
-`nomarchy-theme-sync apply`), one pipeline. State: `settings.autoTheme`
-`{enable, day, night, sunrise, sunset}` in theme-state.json. Slices:
-1. ~~**CLI primitive + schema**~~ ✓ shipped 2026-07-10 —
-   `nomarchy-theme-sync auto` resolves day/night from
-   `settings.autoTheme.{enable,day,night,sunrise,sunset}` and applies (only
-   if different — idempotent, so the timer won't needlessly rebuild);
-   `--which` prints the decision, `--force`/`--no-switch` too. `cmd_apply`
-   core factored into `apply_named` (behavior unchanged). V1 + functional
-   tests (day/night/disabled/missing-slugs, apply writes state, idempotent).
-2. ~~**Timer/hook**~~ ✓ shipped 2026-07-10 — `modules/home/autotheme.nix`:
-   `systemd.user.{service,timer}.nomarchy-auto-theme`, install gated on
-   `settings.autoTheme.enable` (read from state), `OnStartupSec=1min` +
-   `OnCalendar=*:0/15` + `Persistent`. Chose periodic (not exact
-   sunrise/sunset timers) — robust to suspend/DST, and `auto` is idempotent
-   so ticks are cheap. V1: real-config eval shows units land when enabled
-   (OnCalendar `*:0/15`, ExecStart `… auto`), absent when disabled;
-   systemd-analyze validates the schedule. **Real-session check pending**
-   (live timer→`home-manager switch`) — needs a Nomarchy machine, like #76.
-3. **Menu** — Look & Feel › Auto theme: enable/disable, pick day/night
-   themes, set times. Writes state.
+### 79. Auto time-of-day theme pair — all agent work shipped `[blocked:hw]`
+Auto light/dark theme switch through the existing engine, one pipeline
+(`VISION § D`). All 3 slices shipped 2026-07-10; design record in ROADMAP.
+Only the real-session check remains (needs a Nomarchy machine, like #76):
+- **CLI** — `nomarchy-theme-sync auto` (idempotent day/night apply;
+  `--which`/`--force`/`--no-switch`); `cmd_apply` core → `apply_named`.
+- **Timer** — `modules/home/autotheme.nix`: user service+timer, install
+  gated on `settings.autoTheme.enable`, `OnStartupSec=1min` +
+  `OnCalendar=*:0/15` + `Persistent`.
+- **Menu** — Look & Feel › Auto theme: toggle, pick day/night, set times
+  (enable rebuilds to install the timer + `auto --force`; disable is
+  instant `--no-switch`; day/night/times live `--no-switch`).
+
+**V3 remaining:** on a real Nomarchy session — enable from the menu, confirm
+the timer switches day↔night across the sunset/sunrise boundary (and the
+live `home-manager switch` from the timer succeeds).
 
 ### 76. Hibernation default — all agent work shipped `[blocked:hw]`
 Hibernation + zram on by default (product intent, Bernardo 2026-07-10).

agent/JOURNAL.md

@@ -17,6 +17,27 @@ Template:
 
 ---
 
+## 2026-07-10 — #79 slice 3: Look & Feel › Auto theme menu (#79 complete)
+- **Task:** BACKLOG #79 slice 3 — the menu; completes the feature.
+- **Did:** `rofi.nix` — "Auto theme (on/off)" row in Look & Feel + an
+  `autotheme)` submenu: toggle, pick day/night (from
+  `nomarchy-theme-sync list`), set sunrise/sunset (HH:MM input, validated).
+  Enable writes the flag + defaults the summer pair `--no-switch`, then
+  `exec auto --force` — one rebuild installs the timer AND applies the right
+  theme. Disable is instant `--no-switch` (`auto` self-gates; the lingering
+  timer no-ops). Day/night/times are live `--no-switch`.
+- **Verified:** **V1** — HM generation builds (`writeShellScriptBin` bash -n
+  on nomarchy-menu passes) + bash -n on the built menu. **Logic test**
+  (stubbed rofi/theme-sync/notify): selecting "Auto theme (off)" runs exactly
+  `set day summer-day`, `set night summer-night`, `set enable true`
+  (all `--no-switch`), then `auto --force` — the intended one-rebuild path.
+  Disable path is static-clear (set false `--no-switch`, no `auto`); a
+  stateful-stub dynamic test would loop (stub doesn't reflect the flip). V0
+  flake check green. **#79 collapsed to `[blocked:hw]`** (all 3 slices done;
+  only live-session switch remains, needs a Nomarchy machine).
+- **Pending:** V3 real-session (timer switches day↔night across sunset).
+- **Next suggestion:** NEXT head #76/#79 both `[blocked:hw]`; QA/PROPOSED.
+
 ## 2026-07-10 — #79 slice 2: auto-theme systemd timer
 - **Task:** BACKLOG #79 slice 2 — the timer/hook.
 - **Did:** `modules/home/autotheme.nix` (imported in home default.nix):

docs/ROADMAP.md

@@ -286,6 +286,20 @@ Design/decision records and a running log of shipped work (items marked
   **Deliberately NOT shipping more packs by default** (Bernardo 2026-07-10):
   papirus alone is already ~1 GiB and each extra pack adds ~hundreds of MB,
   so variety is opt-in per install, not a default closure cost.
+- ✓ **Auto time-of-day theme (#79, `VISION § D`):** an automatic light/dark
+  theme switch through the **same** engine as a manual apply — no second
+  pipeline. `settings.autoTheme = {enable, day, night, sunrise, sunset}`
+  drives `nomarchy-theme-sync auto`, which picks day vs night by the local
+  clock and applies the preset **only if it differs** (idempotent).
+  `modules/home/autotheme.nix` installs a user timer
+  (`OnStartupSec` + `OnCalendar=*:0/15` + `Persistent`, gated on the state
+  flag) that ticks `auto`; Look & Feel › Auto theme toggles it and picks the
+  pair/times. `cmd_apply`'s core was factored into `apply_named` so `auto`
+  reuses it verbatim. Periodic (not exact sunrise/sunset timers) for
+  robustness to suspend/DST; the idempotent `auto` keeps ticks cheap. Enable
+  rebuilds once (installs the timer + `auto --force`); disable is instant
+  (the flag flips and `auto` self-gates). Live timer→switch is a real-session
+  (V3) check.
 - **Nicer shell out of the box:** ✓ zsh is the default login shell, with a
   starship prompt themed from the JSON, autosuggestions + syntax
   highlighting, and modern-CLI ergonomics — `cat`→bat (theme "ansi", so it

docs/VISION.md

@@ -92,7 +92,7 @@ Reference: [HARDWARE.md](HARDWARE.md) §4–§5, §10.
 | Idea | Intent | Notes |
 |------|--------|-------|
 | **Fewer themes, sharper** | Finish or quarantine neon-glass; invest in whole-swap quality | Contrast stays gated |
-| **Time-of-day pair** | Auto light/dark (e.g. summer-day ↔ summer-night) from schedule | Still one theme engine |
+| **Time-of-day pair** ✓ | Auto light/dark (e.g. summer-day ↔ summer-night) from schedule | ✓ shipped #79 (2026-07-10) — `settings.autoTheme` + timer; still one engine |
 | **Theme switch speed** | Wallpapers artifact split (LATER) if switches still feel slow | GOALS: no second pipeline |
 
 ---

modules/home/rofi.nix

@@ -603,10 +603,15 @@ ${themeRows}
           then row "Night light (on)"  weather-clear-night
           else row "Night light (off)" weather-clear-night
           fi
+          if [ "$(nomarchy-theme-sync get settings.autoTheme.enable 2>/dev/null)" = true ]
+          then row "Auto theme (on)"  preferences-desktop-theme
+          else row "Auto theme (off)" preferences-desktop-theme
+          fi
           back
         } | rofi_menu -show-icons -markup-rows -p "Look & Feel") || exit 0
         case "$choice" in
           "$BACK")           exec "$0" ;;
+          *"Auto theme"*)    exec "$0" autotheme ;;
           *Theme*)           exec "$0" theme ;;
           *"Next wallpaper"*) exec nomarchy-theme-sync bg next ;;
           *"Reset wallpaper"*) exec nomarchy-theme-sync bg auto ;;
@@ -694,6 +699,67 @@ ${themeRows}
           && exec nomarchy-nightlight toggle
         notify-send "Night light" "Not available (nomarchy.nightlight off?)."; exit 0 ;;
 
+      autotheme)
+        # Look & Feel › Auto theme — automatic day/night theme switch
+        # (settings.autoTheme, applied by the nomarchy-auto-theme timer from
+        # autotheme.nix). The enable flag GATES the timer's install, so
+        # turning it *on* must rebuild; day/night/times are read live by
+        # `nomarchy-theme-sync auto`, so those writes are instant
+        # (--no-switch). Enabling writes the flag then `auto --force`, so a
+        # single rebuild both installs the timer and applies the right theme
+        # now. Disabling is instant: the flag flips and `auto` self-gates to
+        # a no-op, so the lingering timer does nothing until the next rebuild.
+        at_get() { nomarchy-theme-sync get "settings.autoTheme.$1" 2>/dev/null; }
+        en=$(at_get enable); day=$(at_get day); night=$(at_get night)
+        sunrise=$(at_get sunrise); sunset=$(at_get sunset)
+        choice=$( {
+          if [ "$en" = true ]
+          then row "Auto theme (on)"  preferences-desktop-theme
+          else row "Auto theme (off)" preferences-desktop-theme
+          fi
+          row "Day theme: ''${day:-— pick}"     weather-clear
+          row "Night theme: ''${night:-— pick}" weather-clear-night
+          row "Sunrise: ''${sunrise:-07:00}"    preferences-system-time
+          row "Sunset: ''${sunset:-20:00}"      preferences-system-time
+          back
+        } | rofi_menu -show-icons -markup-rows -p "Auto theme") || exit 0
+        case "$choice" in
+          "$BACK") exec "$0" lookfeel ;;
+          *"Auto theme"*)
+            if [ "$en" = true ]; then
+              nomarchy-theme-sync --quiet set settings.autoTheme.enable false --no-switch
+              notify-send "Auto theme" "Off — current theme stays."
+              exec "$0" autotheme
+            fi
+            # Need a day + night pair before enabling; default the summer pair.
+            [ -n "$day" ]   || nomarchy-theme-sync --quiet set settings.autoTheme.day summer-day --no-switch
+            [ -n "$night" ] || nomarchy-theme-sync --quiet set settings.autoTheme.night summer-night --no-switch
+            nomarchy-theme-sync --quiet set settings.autoTheme.enable true --no-switch
+            notify-send "Auto theme" "On — applying the theme for now…"
+            exec nomarchy-theme-sync auto --force ;;   # one rebuild: install timer + apply
+          "Day theme"*)
+            slug=$( { nomarchy-theme-sync list; printf '%s\n' "$BACK"; } | rofi_menu -p "Day theme") || exec "$0" autotheme
+            [ "$slug" != "$BACK" ] && [ -n "$slug" ] \
+              && nomarchy-theme-sync --quiet set settings.autoTheme.day "$slug" --no-switch
+            exec "$0" autotheme ;;
+          "Night theme"*)
+            slug=$( { nomarchy-theme-sync list; printf '%s\n' "$BACK"; } | rofi_menu -p "Night theme") || exec "$0" autotheme
+            [ "$slug" != "$BACK" ] && [ -n "$slug" ] \
+              && nomarchy-theme-sync --quiet set settings.autoTheme.night "$slug" --no-switch
+            exec "$0" autotheme ;;
+          "Sunrise"*|"Sunset"*)
+            key=sunrise; label=Sunrise; cur="''${sunrise:-07:00}"
+            case "$choice" in "Sunset"*) key=sunset; label=Sunset; cur="''${sunset:-20:00}" ;; esac
+            t=$(rofi_menu -p "$label HH:MM (now $cur)" < /dev/null) || exec "$0" autotheme
+            case "$t" in
+              [0-2][0-9]:[0-5][0-9])
+                nomarchy-theme-sync --quiet set "settings.autoTheme.$key" "$t" --no-switch ;;
+              "") : ;;
+              *) notify-send "Auto theme" "Ignored '$t' — use HH:MM (24-hour)." ;;
+            esac
+            exec "$0" autotheme ;;
+        esac ;;
+
       autotimezone)
         # Toggle automatic timezone detection (geoclue + automatic-timezoned).
         # A SYSTEM service, so flipping it writes the in-flake flag and runs a