feat: Expand domain models and implement full DTO to domain mapping

This commit significantly expands the domain models to fully represent the quiz structure and implements the complete mapping logic in `QuizMapper` to convert `QuizResponseDto` and its nested DTOs to their corresponding domain models.

Key changes:

- **Domain Layer (`domain` module):**
    - Introduced a `QuizId` value class for type safety.
    - Added comprehensive domain models for all aspects of a quiz, including:
        - `Quiz`: Updated to include all fields from the DTO.
        - `Question`, `Choice`, `Video`, `ImageMetadata`, `MediaItem`, `ChoiceRange`: For question details.
        - `CoverMetadata`, `ExtractedColor`, `Crop`, `Point`: For cover image information.
        - `ContentTags`: For curriculum and generated codes.
        - `Metadata`, `Access`, `FeaturedListMembership`, `LastEdit`, `VersionMetadata`: For quiz metadata.
        - `LanguageInfo`, `Channel`: Common reusable models.
    - Organized domain models into separate files for better maintainability (e.g., `Question.kt`, `CoverMetadata.kt`).
    - Added a placeholder `QuestionModels.kt` to indicate that models were moved.
- **Data Layer (`model:data` module):**
    - Implemented a complete `toDomainModel()` extension function in `QuizMapper.kt` to map all fields from `QuizResponseDto` and its nested DTOs (like `CoverMetadataDto`, `QuestionDto`, etc.) to the new domain models.
    - This includes mapping for lists and nullable fields.
- **App Module (`app` module):**
    - Updated `MainActivity` to access `quizId.value` due to `QuizId` being a value class.
- **Network Layer (`core:network` module):**
    - Changed `QuizResponseDto.uuid` to be non-nullable (`String`) as it's essential for mapping to `QuizId`.
    - Removed `QuizResponse.kt` as DTOs were previously split into individual files.

model/data/src/main/kotlin/dev/adriankuta/kahootquiz/model/data/mappers/QuizMapper.kt

@@ -1,7 +1,176 @@
 package dev.adriankuta.kahootquiz.model.data.mappers
 
-import dev.adriankuta.kahootquiz.core.network.models.QuizResponseDto
-import dev.adriankuta.kahootquiz.domain.models.Quiz
+import dev.adriankuta.kahootquiz.core.network.models.*
+import dev.adriankuta.kahootquiz.domain.models.*
 
 internal fun QuizResponseDto.toDomainModel(): Quiz =
-    Quiz(this.uuid ?: "")
+    Quiz(
+        id = QuizId(uuid),
+        language = language,
+        creator = creator,
+        creatorUsername = creatorUsername,
+        compatibilityLevel = compatibilityLevel,
+        creatorPrimaryUsage = creatorPrimaryUsage,
+        folderId = folderId,
+        themeId = themeId,
+        visibility = visibility,
+        audience = audience,
+        title = title,
+        description = description,
+        quizType = quizType,
+        cover = cover,
+        coverMetadata = coverMetadata?.toDomain(),
+        questions = questions?.map { it.toDomain() } ?: emptyList(),
+        contentTags = contentTags?.toDomain(),
+        metadata = metadata?.toDomain(),
+        resources = resources,
+        slug = slug,
+        languageInfo = languageInfo?.toDomain(),
+        inventoryItemIds = inventoryItemIds ?: emptyList(),
+        channels = channels?.map { it.toDomain() } ?: emptyList(),
+        isValid = isValid,
+        playAsGuest = playAsGuest,
+        hasRestrictedContent = hasRestrictedContent,
+        type = type,
+        created = created,
+        modified = modified
+    )
+
+private fun CoverMetadataDto.toDomain(): CoverMetadata = CoverMetadata(
+    id = id,
+    altText = altText,
+    contentType = contentType,
+    origin = origin,
+    externalRef = externalRef,
+    resources = resources,
+    width = width,
+    height = height,
+    extractedColors = extractedColors?.map { it.toDomain() },
+    blurhash = blurhash,
+    crop = crop?.toDomain()
+)
+
+private fun ExtractedColorDto.toDomain(): ExtractedColor = ExtractedColor(
+    swatch = swatch,
+    rgbHex = rgbHex
+)
+
+private fun CropDto.toDomain(): Crop = Crop(
+    origin = origin?.toDomain(),
+    target = target?.toDomain(),
+    circular = circular
+)
+
+private fun PointDto.toDomain(): Point = Point(x = x, y = y)
+
+private fun ContentTagsDto.toDomain(): ContentTags = ContentTags(
+    curriculumCodes = curriculumCodes,
+    generatedCurriculumCodes = generatedCurriculumCodes
+)
+
+private fun MetadataDto.toDomain(): Metadata = Metadata(
+    access = access?.toDomain(),
+    duplicationProtection = duplicationProtection,
+    featuredListMemberships = featuredListMemberships?.map { it.toDomain() },
+    lastEdit = lastEdit?.toDomain(),
+    versionMetadata = versionMetadata?.toDomain()
+)
+
+private fun AccessDto.toDomain(): Access = Access(
+    groupRead = groupRead,
+    folderGroupIds = folderGroupIds,
+    features = features
+)
+
+private fun FeaturedListMembershipDto.toDomain(): FeaturedListMembership = FeaturedListMembership(
+    list = list,
+    addedAt = addedAt
+)
+
+private fun LastEditDto.toDomain(): LastEdit = LastEdit(
+    editorUserId = editorUserId,
+    editorUsername = editorUsername,
+    editTimestamp = editTimestamp
+)
+
+private fun VersionMetadataDto.toDomain(): VersionMetadata = VersionMetadata(
+    version = version,
+    created = created,
+    creator = creator
+)
+
+private fun LanguageInfoDto.toDomain(): LanguageInfo = LanguageInfo(
+    language = language,
+    lastUpdatedOn = lastUpdatedOn,
+    readAloudSupported = readAloudSupported
+)
+
+private fun ChannelDto.toDomain(): Channel = Channel(id = id)
+
+private fun QuestionDto.toDomain(): Question = Question(
+    type = type,
+    question = question,
+    time = time,
+    points = points,
+    pointsMultiplier = pointsMultiplier,
+    choices = choices?.map { it.toDomain() },
+    layout = layout,
+    image = image,
+    imageMetadata = imageMetadata?.toDomain(),
+    resources = resources,
+    video = video?.toDomain(),
+    questionFormat = questionFormat,
+    languageInfo = languageInfo?.toDomain(),
+    media = media?.map { it.toDomain() },
+    choiceRange = choiceRange?.toDomain()
+)
+
+private fun ChoiceDto.toDomain(): Choice = Choice(
+    answer = answer,
+    correct = correct,
+    languageInfo = languageInfo?.toDomain()
+)
+
+private fun VideoDto.toDomain(): Video = Video(
+    id = id,
+    startTime = startTime,
+    endTime = endTime,
+    service = service,
+    fullUrl = fullUrl
+)
+
+private fun ImageMetadataDto.toDomain(): ImageMetadata = ImageMetadata(
+    id = id,
+    altText = altText,
+    contentType = contentType,
+    origin = origin,
+    externalRef = externalRef,
+    resources = resources,
+    width = width,
+    height = height,
+    effects = effects,
+    crop = crop?.toDomain()
+)
+
+private fun MediaItemDto.toDomain(): MediaItem = MediaItem(
+    type = type,
+    zIndex = zIndex,
+    isColorOnly = isColorOnly,
+    id = id,
+    altText = altText,
+    contentType = contentType,
+    origin = origin,
+    externalRef = externalRef,
+    resources = resources,
+    width = width,
+    height = height,
+    crop = crop?.toDomain()
+)
+
+private fun ChoiceRangeDto.toDomain(): ChoiceRange = ChoiceRange(
+    start = start,
+    end = end,
+    step = step,
+    correct = correct,
+    tolerance = tolerance
+)