Implement complete bookmark functionality for Bible reading

Add both chapter-level and verse-level bookmarking capabilities:

Database Changes:
- Add ChapterBookmark table for chapter-level bookmarks
- Update schema with proper relationships to User and BibleBook models
- Maintain existing Bookmark table for verse-level bookmarks

API Endpoints:
- /api/bookmarks/chapter (GET, POST, DELETE) with check endpoint
- /api/bookmarks/verse (GET, POST, DELETE) with check and bulk-check endpoints
- JWT authentication required for all bookmark operations
- Multilingual error messages (Romanian/English)

Frontend Implementation:
- Chapter bookmark button in Bible page header with visual state feedback
- Individual verse bookmark icons with hover-to-reveal UI
- Highlighted background for bookmarked verses
- Efficient bulk checking for verse bookmarks per chapter
- Real-time UI updates without page refresh

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

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

prisma/schema.prisma

@@ -21,6 +21,7 @@ model User {
 
   sessions        Session[]
   bookmarks       Bookmark[]
+  chapterBookmarks ChapterBookmark[]
   notes           Note[]
   chatMessages    ChatMessage[]
   prayerRequests  PrayerRequest[]
@@ -68,6 +69,7 @@ model BibleBook {
   orderNum    Int
   bookKey     String   // For cross-version matching (e.g., "genesis", "exodus")
   chapters    BibleChapter[]
+  chapterBookmarks ChapterBookmark[]
 
   version     BibleVersion @relation(fields: [versionId], references: [id])
 
@@ -151,6 +153,21 @@ model Bookmark {
   @@index([userId])
 }
 
+model ChapterBookmark {
+  id          String   @id @default(uuid())
+  userId      String
+  bookId      String
+  chapterNum  Int
+  note        String?
+  createdAt   DateTime @default(now())
+
+  user        User     @relation(fields: [userId], references: [id], onDelete: Cascade)
+  book        BibleBook @relation(fields: [bookId], references: [id])
+
+  @@unique([userId, bookId, chapterNum])
+  @@index([userId])
+}
+
 model Note {
   id          String   @id @default(uuid())
   userId      String