Settings: a settings window, its sections, a search, and what fills them

SettingsLayout lists sections down the side and shows the open one, the
list going above the page in a narrow box; SettingsSection and
SettingsRow title and hold settings, a row's control wrapping under its
name. SettingsSearch finds a setting by its name or words and opens its
section. ThemeSelector, AccentColorPicker, FontSizeControl and
DensitySelector set the look; KeyboardShortcutsList finds shortcuts by
every word; ProxySettings, PrivacySettings, NotificationSettings,
StartupSettings, StorageSettings with its clear, ImportExportSettings,
ResetToDefault, FeatureFlags and DeveloperModeToggle fill the rest.
Every handler a control needs is required and fails loud when missing.
ColorPalette wraps its swatches in a row capped at its columns, so it
keeps their size in a box sized by its content, and its swatches carry
the palette's id. ThemeSwitcher points here: src/theme sits under the
chapters that draw with buttons.

tasks/ch31-43.md

@@ -146,27 +146,27 @@
 
 ## T35 Settings — `src/settings`
 
-- [ ] SettingsLayout
-- [ ] SettingsSection
-- [ ] SettingsRow
-- [ ] SettingsSearch
-- [ ] ThemeSelector → `theme::ThemeSwitcher`
-- [ ] AccentColorPicker
-- [ ] FontSizeControl
-- [ ] FontFamilySelect → `forms::FontPicker`
-- [ ] DensitySelector
-- [ ] LanguageSelector → `forms::Combobox::languages` (T06f)
-- [ ] KeyboardShortcutsList
-- [ ] ShortcutEditor → `editor::KeybindingsEditor`
-- [ ] ProxySettings
-- [ ] StorageSettings / CacheClear
-- [ ] PrivacySettings
-- [ ] NotificationSettings
-- [ ] StartupSettings
-- [ ] ImportExportSettings
-- [ ] ResetToDefault
-- [ ] AdvancedSettings / FeatureFlags
-- [ ] DeveloperMode Toggle
+- [x] SettingsLayout
+- [x] SettingsSection
+- [x] SettingsRow
+- [x] SettingsSearch
+- [x] ThemeSelector (T39's ThemeSwitcher points here)
+- [x] AccentColorPicker
+- [x] FontSizeControl
+- [x] FontFamilySelect → `forms::FontPicker`
+- [x] DensitySelector
+- [x] LanguageSelector → `forms::Combobox::languages` (T06f)
+- [x] KeyboardShortcutsList
+- [x] ShortcutEditor → `editor::KeybindingsEditor`
+- [x] ProxySettings
+- [x] StorageSettings / CacheClear
+- [x] PrivacySettings
+- [x] NotificationSettings
+- [x] StartupSettings
+- [x] ImportExportSettings
+- [x] ResetToDefault
+- [x] AdvancedSettings / FeatureFlags
+- [x] DeveloperMode Toggle
 
 ## T36 Account — `src/account`
 
@@ -237,7 +237,7 @@
 ## T39 Theme — `src/theme`
 
 - [x] ThemeProvider (T00)
-- [ ] ThemeSwitcher
+- [ ] ThemeSwitcher → `settings::ThemeSelector` (T35)
 - [x] ColorTokens / DesignTokens (T00)
 - [ ] ThemeEditor
 - [ ] ThemeImporter — VS Code theme JSON