Convert British spellings to American across the repo

colour -> color, behaviour -> behavior, centre -> center, favourite ->
favorite, and about twenty other pairs, applied consistently across
comments, docs, error/UI copy, and a handful of QML identifiers that
used the British spelling as their actual name: SystemSettings'
serialiseValue/serialiseTable/normaliseGradient, Displays'
normaliseModes, Wallpaper's normalisePolicy, SettingsBackup's
serialiseHomeState, DateTime's ntpSynchronised property, Clipboard's
_normalise helper, and ShortcutCapture's cancelled signal (with its
onCancelled handler in ShortcutsPage.qml). Every call site and the two
tests that assert on the literal source text (settings-ownership and
settings-backup-live contracts) were updated in lockstep.

Left untouched: config/dot/espanso/match/packages/misspell-en/ is a
vendored third-party autocorrect dictionary -- its entries are typo
corrections, not our prose, and rewriting them would fight the
package's own purpose (and any future re-sync from upstream).

The already-American `favorites` property (Home page pinned
accessories) was never actually misspelled -- only nearby comments and
error strings said "favourites" -- so no data migration was needed
there.

Claude-Session: https://claude.ai/code/session_01E6TJUAh41HaP25MVHWkhRZ

docs/superpowers/plans/2026-08-17-panama-cohesion.md

@@ -15,10 +15,10 @@ holds the shipped defaults; one JSON file is the truth both sides read.
 - Verify every write by reading the value back (`hyprctl getoption`), never by
   trusting an exit code.
 - No UI-supplied string is interpolated into `eval`, a shell command, or a config
-  value. Numbers range-checked, choices allow-listed, colours hex-validated.
+  value. Numbers range-checked, choices allow-listed, colors hex-validated.
 - A missing or malformed `settings.json` degrades to shipped defaults. The Lua
   read is `pcall`-wrapped so it can never take down the compositor config.
-- Tokyo Night Moon and Prism stay the only identity; customisation adjusts its
+- Tokyo Night Moon and Prism stay the only identity; customization adjusts its
   parameters, it does not replace it.
 - Motion stays event-driven at every setting. No idle repaint.
 - Do not restart the running Quickshell process during development; it hot-reloads.
@@ -30,7 +30,7 @@ holds the shipped defaults; one JSON file is the truth both sides read.
 ## Stage 0 — Stop the lying (ship first, standalone)
 
 The display-policy toggles report success while doing nothing. This is a
-correctness bug in shipped behaviour and does not depend on any of the
+correctness bug in shipped behavior and does not depend on any of the
 architecture below.
 
 **Files:** Modify `config/dot/quickshell/services/SystemSettings.qml`;
@@ -40,7 +40,7 @@ Test `tests/quickshell/settings-hyprland-write-contract.sh`
       asserts via `hyprctl getoption` that the compositor value actually changed —
       and that a rejected write leaves `lastError` non-empty.
 - [x] Run it; confirm it fails against the current `hyprctl keyword` implementation.
-- [x] Add a single `applyOptions(values)` boundary that serialises validated values
+- [x] Add a single `applyOptions(values)` boundary that serializes validated values
       into `hl.config{}` and runs them through `hyprctl eval`.
 - [x] Route `setAutoHdr`, `setVrrPolicy`, and `setDirectScanoutPolicy` through it.
 - [x] Treat "wrote it back and read it back equal" as the only success condition;
@@ -134,9 +134,9 @@ Test `tests/hypr/prefs-fallback-contract.sh`
 - [x] Implement a dependency-free JSON reader exposing `prefs.get(key, fallback)`,
       `pcall`-wrapped, reading `$XDG_CONFIG_HOME/panama/settings.json`.
 - [x] Require it first in `hyprland.lua`, before `looks`.
-- [x] Convert the appearance and behaviour literals in `looks.lua` and `input.lua`
+- [x] Convert the appearance and behavior literals in `looks.lua` and `input.lua`
       to `prefs.get("<key>", <current literal>)`, keeping every current value as
-      the fallback so shipped behaviour is byte-identical.
+      the fallback so shipped behavior is byte-identical.
 - [x] Extend `PreferenceSchema.qml` with the Hyprland-owned keys, each carrying
       the `hl.config` path it maps to.
 - [x] Have `SystemSettings` derive its `eval` payload from that mapping, so a new
@@ -208,7 +208,7 @@ Modify all eleven `*Page.qml`; Test `tests/quickshell/settings-rows-contract.sh`
 - [ ] Move the remaining pages (Home, Displays, Connectivity, Sound,
       Notifications, Screen Intelligence, Services, About) onto `SettingsPage`.
 
-**Exit criteria:** no shipped behaviour value is reachable only by editing a file.
+**Exit criteria:** no shipped behavior value is reachable only by editing a file.
 
 **Landed (first pass).** `SettingsPage` plus `ToggleRow`, `SliderRow`,
 `ChoiceRow`, `ActionRow`, and `TextRow`. A row names a schema key and needs
@@ -218,7 +218,7 @@ explanation, bounds, and unit from the schema, and writes through
 apply-and-verify and local keys straight to the store. Rows never need to know
 which kind they hold.
 
-`DesktopPreview` is the direction-B centrepiece: two tiled windows drawn at the
+`DesktopPreview` is the direction-B centerpiece: two tiled windows drawn at the
 settings actually in effect, scaled by the ratio between the preview's width and
 the real monitor's, so a 10px gap on a 4500px display looks as small as it is.