feat: implement Phase 1 Bible reader improvements (2025 standards)

## Typography Enhancements
- Add letter spacing control (0-2px, default 0.5px for WCAG compliance)
- Add word spacing control (0-4px, default 0px)
- Add paragraph spacing control (1.0-2.5x line height, default 1.8x)
- Add max line length control (50-100ch, default 75ch for optimal readability)
- Apply WCAG 2.1 SC 1.4.12 text spacing recommendations

## Multi-Color Highlighting System
- Implement 7-color highlight palette (yellow, green, blue, purple, orange, pink, red)
- Theme-aware highlight colors (light/dark/sepia modes)
- Persistent visual highlights with database storage
- Color picker UI with current highlight indicator
- Support for highlight notes and tags (infrastructure ready)
- Bulk highlight loading for performance
- Add/update/remove highlight functionality

## Database Schema
- Add Highlight model with verse relationship
- Support for color, note, tags, and timestamps
- Unique constraint per user-verse pair
- Proper indexing for performance

## API Routes
- POST /api/highlights - Create new highlight
- GET /api/highlights - Get all user highlights
- POST /api/highlights/bulk - Bulk fetch highlights for verses
- PUT /api/highlights/[id] - Update highlight color/note/tags
- DELETE /api/highlights/[id] - Remove highlight

## UI Improvements
- Enhanced settings dialog with new typography controls
- Highlight color picker menu
- Verse menu updated with highlight option
- Visual feedback for highlighted verses
- Remove highlight button in color picker

Note: Database migration pending - run `npx prisma db push` to apply schema

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

prisma/schema.prisma

@@ -23,6 +23,7 @@ model User {
   sessions        Session[]
   bookmarks       Bookmark[]
   chapterBookmarks ChapterBookmark[]
+  highlights      Highlight[]
   notes           Note[]
   chatMessages    ChatMessage[]
   chatConversations ChatConversation[]
@@ -116,6 +117,7 @@ model BibleVerse {
   chapter     BibleChapter @relation(fields: [chapterId], references: [id])
   bookmarks   Bookmark[]
   notes       Note[]
+  highlights  Highlight[]
 
   @@unique([chapterId, verseNum])
   @@index([chapterId])
@@ -210,6 +212,24 @@ model ChapterBookmark {
   @@index([userId])
 }
 
+model Highlight {
+  id          String   @id @default(uuid())
+  userId      String
+  verseId     String
+  color       String   // yellow, green, blue, purple, orange, pink, red
+  note        String?  @db.Text
+  tags        String[] @default([])
+  createdAt   DateTime @default(now())
+  updatedAt   DateTime @updatedAt
+
+  user        User     @relation(fields: [userId], references: [id], onDelete: Cascade)
+  verse       BibleVerse @relation(fields: [verseId], references: [id])
+
+  @@unique([userId, verseId])
+  @@index([userId])
+  @@index([verseId])
+}
+
 model Note {
   id          String   @id @default(uuid())
   userId      String