Redesign the Reader; add ESV

New reading surface with paper/sepia/dark themes, slim top and bottom bars,
and sheets for navigation, search, settings, audio and per-verse study tools.
Plan progress is built into the reader. Page-flip mode removed. ESV added via
the server-side proxy (ESV_API_KEY).

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

src/components/reader/readerThemes.js

@@ -0,0 +1,18 @@
+// Reader colour themes, applied as CSS variables on the reader root so every
+// reader component can use bg-[var(--r-bg)] etc. and stay in sync.
+export const READER_THEMES = {
+  paper: {
+    label: 'Paper',
+    vars: { '--r-bg': '#faf7f0', '--r-text': '#2b2620', '--r-sub': '#7d7466', '--r-accent': '#b4532a', '--r-bar': '#f1ece0', '--r-line': '#e0d8c6', '--r-hl': '#f6e7a8', '--r-on': '#ffffff' },
+  },
+  sepia: {
+    label: 'Sepia',
+    vars: { '--r-bg': '#f1e4c8', '--r-text': '#3b2f1c', '--r-sub': '#7d6b48', '--r-accent': '#9a4a1e', '--r-bar': '#e8d8b6', '--r-line': '#d5c197', '--r-hl': '#e9cf85', '--r-on': '#ffffff' },
+  },
+  dark: {
+    label: 'Dark',
+    vars: { '--r-bg': '#1c1b19', '--r-text': '#e6e1d6', '--r-sub': '#9a9385', '--r-accent': '#e0895c', '--r-bar': '#262421', '--r-line': '#3a3733', '--r-hl': '#4a4224', '--r-on': '#1c1b19' },
+  },
+};
+
+export const themeVars = (id) => (READER_THEMES[id] ?? READER_THEMES.paper).vars;