feat(themes): community Theme Store + semantic-token refactor (#1009)

* feat(themes): add semantic tokens for the theme-store contract (B0 P1)

Additive: define --highlight, --accent-2, --bg-deep, --bg-elevated and
--text-on-accent on the :root base as --ctp-* mappings. They resolve
per-theme automatically and nothing consumes them yet (zero behaviour
change) — groundwork for replacing direct --ctp-* use in components.

* refactor(themes): components consume semantic tokens, not --ctp-* (B0 P2)

Replace every direct --ctp-* reference in component/layout/track CSS and
TSX inline styles with the readable semantic token (--bg-app, --accent,
--highlight, --text-on-accent, …). --ctp-* now survives only as the
Catppuccin palette layer the base maps from, and as the deliberate
categorical rainbow in Composers/Genres/artistsHelpers (left untouched).

This is the readable contract surface for the community theme store.
Divergences (theme set a semantic var != its --ctp- source) are
corrections — the element now uses the theme's real semantic colour.

* feat(themes): add player-bar title/artist color tokens

New optional --player-title / --player-artist, defaulting to --text-primary / --text-secondary so nothing changes unless a theme overrides them. Lets a theme give the now-playing readout its own colour as a plain token.

* refactor(themes): token-only theme library (flatten, whitelist, one file per theme)

Turn every built-in theme into a single self-contained [data-theme] var block of semantic whitelist tokens (plus the internal --ctp-* palette layer):

- Flatten all themes: drop structural override rules, @keyframes, and global-token overrides (radius / shadow-elevation / transition / spacing / font / focus-ring). Signature player-bar readout colours are preserved via the new --player-title / --player-artist tokens.

- Normalize the var blocks to the semantic whitelist: drop the alternate token vocabulary (nav-active / scrollbar / bg-input / success / border-default / ...); rename --success -> --positive and --border-default -> --border where no whitelist equivalent was set. Migrate the few components that read those tokens to the whitelist equivalents.

- Split multi-theme files so each theme ships as its own file, making the built-in set 1:1 with the per-theme store packaging.

Kept as-is (built-in, not flattened): the two colour-blind-safe accessibility themes, plus the two curated core skins.

* chore(themes): remove seven themes retired after the token refactor

These themes leaned on heavy structural overrides and were dropped rather than flattened. Full removal each: the CSS file(s), the index.css import, the Theme type union, and the ThemePicker entry.

* feat(themes): granular tokens — track lists

Wire track rows to per-region tokens: row hover (--row-hover), the now-playing
row + indicator (--row-playing-bg / --row-playing-text), track title/artist/
number/duration text, column-header text, row dividers, and the resize-handle
active colour. Covers the desktop tracklist, the shared song-row (Tracks hub /
search), and the mobile tracklist. Drop a baked border fallback. Visual no-op.

* feat(themes): granular tokens — cards

Wire album and artist cards to per-region tokens (--card-hover-border,
--card-title, --card-subtitle, --card-placeholder-bg). Visual no-op.

* fix(themes): drop undefined/baked colour aliases

Replace the undefined --bg-surface (resolved to nothing — broken placeholder
backgrounds and filter input) with --card-placeholder-bg / --input-bg, and the
baked-hex aliases --color-error / --color-warning with --danger / --warning so
themes can actually recolour them.

* feat(themes): Spectrum demo theme + trim unused cascade tokens

Add a loud built-in demo theme that gives each region its own hue (sidebar
green, player pink, lists cyan, cards gold, menus red, controls blue) so the
per-region granularity is obvious when you switch to it. Drop two unused
cascade tokens (--sidebar-text-active, --row-active-bg) and the unused
on-media block (those media surfaces stay static by design).

* style(themes): make Spectrum demo brutally loud

Full-saturation neon per region (toxic green sidebar, magenta player, cyan
lists, acid-yellow cards, blood-red menus, electric-blue controls, purple
scrollbar) so the per-region separation is unmistakable. The earlier soft
tints were too subtle to read.

* feat(themes): name the granular demo theme Braindead

* feat(themes): granular per-region tokens — cascade layer + sidebar

Add an optional per-region token layer (semantic-cascade.css) so a theme can
recolour individual regions — sidebar hover, player controls, list rows,
menus, inputs, on-media surfaces — independently of the global tokens. Every
token defaults to its base token (or a media-safe literal), so this is a
visual no-op until a theme overrides one; it only adds control points.

Wire the sidebar region as the first consumer and drop the baked grey
fallbacks (--bg-tertiary, etc.) that no theme could reach.

* feat(themes): granular tokens — controls, menus, scrollbar

Wire inputs, buttons, sliders, the custom-select, context menus, submenus and
modals to per-region tokens, and tokenise the scrollbar. Complete B0 by
dropping the last direct --ctp-* references in the input/button/progress/
scrollbar utility CSS.

Fix three undefined-token bugs that fell back to nothing (so no theme could
reach them): --surface-2 (context-menu hover had no highlight), --bg-surface
(submenu create-input had no background), and the baked grey fallbacks in the
custom-select. Every other new token defaults to today's value — a visual
no-op that only adds override points.

* feat(themes): granular tokens — player bar

Wire the desktop player bar's transport controls, time toggle, and overflow
menu to per-region tokens (--player-control, --player-time-toggle-*, etc.).
Fix the undefined --surface-hover/--surface-active grey fallbacks on the time
toggle. Visual no-op; defaults match today's values.

* chore(themes): remove empty theme stub files

Six theme CSS files were reduced to comment-only stubs by the flatten
sweep but their files and @import lines remained. Five are empty
structural companions of now-flattened themes (morpheus, p-dvd,
aero-glass, luna-teal) and two are orphans of cut themes
(order-of-the-phoenix, pandora). Removed the files and their imports.

* feat(themes): runtime injection foundation for the theme store

Plumbing for installed community themes ahead of the in-app store UI,
nothing user-visible yet:

- installedThemesStore: persisted (localStorage) record of installed
  community themes incl. their CSS text, so an active community theme is
  available synchronously at startup (no flash, fully offline).
- themeInjection: reconcile <head> <style data-installed-theme> elements
  with the store; lightweight defense-in-depth sanitize on top of CI.
- themeRegistry: jsDelivr registry client with a 12h localStorage cache
  and stale-on-error fallback.
- App: inject installed themes before applying data-theme, in both webviews.
- themeStore: widen the Theme type to accept dynamic installed ids.

* feat(themes): dedicated Themes settings tab

Move theme selection and the day/night scheduler out of Appearance into
a new dedicated Themes tab — the future home of the community Theme Store.
Appearance keeps grid columns, visual options, UI scale, font and seekbar.

- ThemesTab: theme picker + scheduler (relocated verbatim).
- AppearanceTab: drop the two relocated sections + now-unused imports.
- Register the tab in settingsTabs (Tab union, resolveTab, search index)
  and Settings (tab bar, render, label map).
- i18n: settings.tabThemes in all 9 locales.

* feat(themes): community Theme Store browse + install

Add the Theme Store section to the Themes tab:

- Fetch the jsDelivr registry (12h cache, stale-on-error fallback).
- Search by name/author/description + filter by light/dark + refresh.
- Per-row CDN thumbnail, name, author, description and actions:
  Install / Apply / Update / Uninstall. Installing fetches the CSS,
  persists it (localStorage) and the runtime injection applies it;
  uninstalling the active theme falls back to the matching core.
- Rating slot left reserved (deferred).
- i18n: themeStore* keys in all 9 locales.

* feat(themes): slim bundle to fixed cores + flat Themes tab

Remove the 86 store palettes (incl. braindead) from the app bundle — the
CSS files, their index.css imports, the Theme union and the picker data —
leaving only the six fixed cores (Catppuccin Mocha/Latte, Kanagawa Wave,
Stark HUD, Vision Dark/Navy). Everything else installs from the store.

Themes tab is rebuilt flat (no collapsible accordions):
- "Your Themes": one card grid of the fixed cores + installed community
  themes; click to apply, uninstall on community ones (active theme falls
  back to the matching core). Catppuccin prefix on Mocha/Latte; a CVD-safe
  pill on the colour-blind-safe Vision themes.
- Scheduler day/night options include installed themes.
- Theme Store: alphabetical order, thumbnail lightbox, and a submit hint
  above the search linking to the themes repository.
- Nav order: Servers, Library, Audio, Themes, Appearance, Lyrics, …
- ThemePicker accordion removed; fixed-theme data moved to fixedThemes.ts.
- i18n for all new strings across 9 locales.

* feat(themes): reset removed-from-bundle themes to a bundled fallback

After slimming the bundle to the six fixed core themes, a profile upgraded
from an older build may have an active or scheduler theme that is now
store-only and not installed — it has no [data-theme] block and would render
as unstyled :root. Reset any theme/themeDay/themeNight that is neither bundled
nor installed to a bundled fallback: Mocha for the main + night slots, Latte
for the day slot. Runs synchronously in runPreReactBootstrap, rewriting the
persisted selection in localStorage before React mounts (no flash; Zustand
rehydrates after first paint). No auto-install and no network — the fallback
is always a bundled theme, so it works offline.

* feat(themes): floating back-to-top button on the Themes tab

The Themes tab can get long (theme grid + scheduler + full store list), so
add a floating back-to-top affordance that appears once the page is scrolled
and smooth-scrolls to the top. It is portalled into the route host and
positioned absolute against it — the main scroll viewport sets contain: paint,
which would otherwise make position: fixed resolve against the scrolling box
and drift with the content. Reusable component (scroll viewport id + threshold
props); i18n common.backToTop added in all nine locales.

* feat(themes): accessibility + state polish for the Theme Store

- Reuse the shared CoverLightbox for the thumbnail preview instead of a
  second inline dialog — gains a visible close button and a focus-managed,
  portalled dialog, and drops duplicated markup.
- Theme cards expose aria-pressed so assistive tech announces the selected
  theme, not just the visual check.
- Transient store messages get live-region roles (loading/empty/install
  failure = status, fetch error = alert).
- Thumbnails degrade gracefully when offline/missing (hide the broken-image
  glyph; the thumbnail button no longer stretches with the row, so its
  background can't show as letterbox bars).

* feat(themes): larger store-row thumbnails (120x75 -> 200x125)

The list previews were too small to make a theme out; bump the display size
(same 1.6 aspect). Thumbnails are now served at 720x450, so the larger
display stays crisp.

* fix(themes): bust thumbnail cache on registry change

jsDelivr serves theme thumbnails with a 7-day max-age, so when a thumbnail
is updated the webview keeps showing its cached old image (the path is
unchanged). Append the registry's generatedAt as a cache-busting query to
the thumbnail URLs (list + lightbox); it changes on every themes push, so a
registry refresh makes the webview re-fetch and reflect the current CDN
image instead of a stale one.

* docs(themes): changelog + credits for the Theme Store

Add the 1.48.0 "Themes — community Theme Store" changelog entry (PR #1009)
and the matching line in the Psychotoxical credits.

* fix(themes): address PR review (uninstall hygiene, validation, polish)

Uninstall/scheduler & validation:
- uninstallTheme() repairs every selection slot (active + day + night), not
  just the manual one, and is shared by both uninstall buttons (dedup).
- Validate theme CSS at install time and skip persisting CSS that won't inject
  (no more "installed/active but renders nothing" with no feedback).
- Harden the runtime validator: exactly one rule, scoped exactly to the
  theme's [data-theme='<id>'] selector (no unscoped/foreign selectors), no
  at-rules, url() only data:, no expression()/javascript:, size-capped.

Tokens & polish:
- Fix three dangling undefined tokens (--surface-2 x2, --bg-surface).
- Finish the warning/success token sweep (--warning / --positive, themeable).
- Apply the active theme synchronously before React mounts (no first-frame
  flash) and inject installed themes up front.
- One-time, dismissible notice when the slim-bundle migration reset a theme.
- Update badge uses semver, not string inequality.
- Offline/stale indicator in the store; cross-window theme sync; drop the now
  dead REMOVED_THEME_REMAP and Card.mode field.

Tests: themeInjection (validator + sync), themeRegistry (cache/force/stale/
malformed), uninstallTheme (slot repair), migration notice. i18n in all nine
locales. Full suite green (1755 tests).

* test(bootstrap): cover startup theme apply + cross-window sync

The review fixes added applyThemeAtStartup / installCrossWindowThemeSync to
bootstrap.ts (a hot-path file) without tests, dropping its coverage to 68.3%
and failing the frontend hot-path coverage gate (>=70%). Add unit tests for
both (and the no-op / malformed-storage paths); bootstrap.ts is back to ~98%.

src/locales/nb/settings.ts

@@ -320,6 +320,36 @@ export const settings = {
   tabPersonalisation: 'Personalisering',
   tabIntegrations: 'Integrasjoner',
   tabAppearance: 'Utseende',
+  tabThemes: 'Temaer',
+  themesYourThemesTitle: 'Dine temaer',
+  themesCvdTooltip: 'Fargeblind-sikker – deuteranopi, protanopi, tritanopi',
+  themeStoreTitle: 'Temabutikk',
+  themeStoreSubmitText: 'Laget ditt eget tema? Del det med fellesskapet — mer info i tema-repoet.',
+  themeStoreSubmitLink: 'Åpne tema-repoet',
+  themeStoreSearchPlaceholder: 'Søk i temaer…',
+  themeStoreFilterMode: 'Filtrer etter modus',
+  themeStoreModeAll: 'Alle',
+  themeStoreModeDark: 'Mørk',
+  themeStoreModeLight: 'Lys',
+  themeStoreRefresh: 'Oppdater',
+  themeStoreLoading: 'Laster temaer…',
+  themeStoreError: 'Kunne ikke laste temabutikken. Sjekk tilkoblingen din.',
+  themeStoreRetry: 'Prøv igjen',
+  themeStoreEmpty: 'Ingen temaer samsvarer med filtrene dine.',
+  themeStoreActive: 'Aktiv',
+  themeStoreEnlarge: 'Forstørr forhåndsvisning',
+  themeStoreByAuthor: 'av {{author}}',
+  themeMigrationNoticeTitle: 'Temaet er flyttet til butikken',
+  themeMigrationNoticeBody: '{{themes}} følger ikke lenger med appen. Du kan installere det på nytt fra temabutikken (Innstillinger → Temaer), eller velge et annet tema.',
+  themeMigrationNoticeOpen: 'Åpne temabutikken',
+  themeStoreOffline: 'Viser den sist bufrede katalogen — du ser ut til å være frakoblet.',
+  themeStoreInstall: 'Installer',
+  themeStoreInstalling: 'Installerer…',
+  themeStoreApply: 'Bruk',
+  themeStoreUpdate: 'Oppdater',
+  themeStoreUpdating: 'Oppdaterer…',
+  themeStoreUninstall: 'Avinstaller',
+  themeStoreInstallFailed: 'Installasjonen mislyktes',
   tabStorage: 'Frakoblet & Cache',
   inputKeybindingsTitle: 'Tastatursnarveier',
   aboutContributorsCount_one: '{{count}} bidrag',