Seconds per clock, and type that scales with the bar height

Seconds move from one bar-wide switch to a per-clock setting. A clock's own
`showSeconds` wins, the top-level one is the default for clocks with no
opinion, and the centre clock gets `local.showSeconds` since it has no entry in
`clocks[]`. An explicit false on a clock beats a true default, so the check is
for the property's presence rather than its truthiness.

The tick rate follows what is actually displayed: `anyShowsSeconds()` decides
between a per-second and a per-minute SystemClock, so a bar showing no seconds
does not wake the shell sixty times as often to redraw an identical minute.

`barSize` is now editable from the popup, and everything drawn on the bar is
sized against the theme's own bar height rather than pinned to the theme's
12px type. A taller bar carries proportionally larger text, gaps and rule; at
the theme's own height the scale is exactly 1, so nothing moves. Heights are
clamped to 12-120 rather than rejected, so a value the editor can produce can
never be one the config layer silently discards.

Fixes a latent bug this surfaced: updateRow() rebuilt a draft row from a fixed
pair of fields, so editing a clock's label would have thrown away its own
seconds setting. It now copies every key the row had.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MhxtL7WzL5XmuTd8GHbcTY

README.md

@@ -21,8 +21,12 @@ tiles windows above it exactly as it does for the top bar.
   carries no label.
 - **Dimmed outside working hours**, evaluated in each clock's *own* timezone
   (weekends included), so a glance tells you who is actually around.
+- **Seconds per clock.** Any clock can show `HH:MM:SS` on its own, including
+  your local one. The bar only drops to a per-second tick when something is
+  actually displaying seconds.
 - **Themed.** Colours, fonts, spacing and bar height all come from the active
-  Omarchy theme; it follows a theme switch with no restart.
+  Omarchy theme; it follows a theme switch with no restart. Set your own bar
+  height and the type and spacing scale with it.
 
 ## Install
 
@@ -65,11 +69,12 @@ shows that zone's current offset so you can see the effect before saving.
     { "label": "NYC", "timezone": "America/New_York" },
     { "label": "SG",  "timezone": "Asia/Singapore" },
     { "label": "AUS", "timezone": "Australia/Sydney" },
-    { "label": "NZ",  "timezone": "Pacific/Auckland" }
+    { "label": "NZ",  "timezone": "Pacific/Auckland", "showSeconds": true }
   ],
   "workingHours": { "start": 8, "end": 18, "workdays": [1, 2, 3, 4, 5] },
   "dimOutsideWorkingHours": true,
   "showSeconds": false,
+  "local": { "showSeconds": false },
   "barSize": 0
 }
 ```
@@ -78,11 +83,18 @@ shows that zone's current offset so you can see the effect before saving.
 |---|---|
 | `clocks[].label` | Shown left of the time. Defaults to the last part of the zone name. |
 | `clocks[].timezone` | Any IANA zone (`timedatectl list-timezones`). |
+| `clocks[].showSeconds` | Seconds on this clock. Omit it to inherit the bar-wide default below. |
 | `workingHours.start` / `.end` | Hours, 0–24, in each clock's own zone. A window that wraps midnight (`22`–`6`) is understood. |
 | `workingHours.workdays` | Days counted as working. `0` = Sunday. |
 | `dimOutsideWorkingHours` | Mute clocks outside that window. |
-| `showSeconds` | `HH:MM:SS` and a per-second tick, instead of `HH:MM`. |
-| `barSize` | Bar height in px. `0` follows the theme's bar height. |
+| `showSeconds` | The bar-wide default for seconds, for clocks that do not set their own. |
+| `local.showSeconds` | Seconds on your local clock, which has no entry in `clocks[]`. |
+| `barSize` | Bar height in px. `0` follows the theme's. Otherwise 12–120; text and spacing scale with it. |
+
+Seconds resolve per clock: a clock's own `showSeconds` wins, otherwise the
+bar-wide default applies. An explicit `false` on a clock beats a `true`
+default. The bar ticks once a minute unless something on it is showing
+seconds — nothing pays for a per-second redraw it does not use.
 
 There is no `left` / `right` setting: which side a clock lands on is a fact
 about its offset, not a preference.