feat(ai): massive architecture overhaul, new providers, and generation tuning

[VoidX3D]

Overview

Removes the unused AiMetadataGenerator feature, adds generation parameters (temperature, topP, topK, maxTokens, presence/frequency penalty) and song data configuration to the AI settings UI, adds OLLAMA and CUSTOM provider support, overhauls all AI prompts with chain-of-thought reasoning and few-shot examples, and fixes two CI compilation errors.

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Breaking Changes

• AiMetadataGenerator deleted — the AI metadata enhancement feature is removed entirely. All 25+ call sites across screens, holders, and view models have been stripped.

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What's New

AI Provider Support

• OLLAMA provider — added to AiProvider enum, AiClientFactory, provider fallback chain, preferences, and settings UI
• CUSTOM provider — allows connecting to any OpenAI-compatible endpoint via configurable base URL
• SearchableModelSelector composable — searchable model dropdown for providers with dynamic model lists
• Base URL configuration — text field for custom base URLs (visible for OLLAMA and CUSTOM providers)

AI Settings UI

• Generation Parameters section — sliders/fields for temperature, topP, topK, maxTokens, presence penalty, frequency penalty
• Song Data Configuration section — sample size selector (10–120), digest mode toggle (safe/full), extended fields toggle
• All persisted globally (not per-provider) via DataStore prefs

Generation Parameters (Client API)

• Added topP, topK, maxTokens, presencePenalty, frequencyPenalty to:
  • AiClient interface
  • GenericOpenAiClient.ChatRequest (serialized to JSON)
  • GeminiAiClient.GenerationConfig (serialized to JSON)
• AiHandler fetches gen params from preferences and passes them through to generateWithRecovery
• Usage tracking records actual model name (result.modelUsed) instead of provider name

Prompt Engineering

• AiSystemPromptEngine overhauled with:
  • Chain-of-thought reasoning instructions per type (GENERAL, PLAYLIST, METADATA, DIGEST, CHAT)
  • Few-shot examples for playlist, metadata, and digest generation
  • Quality guardrails (no markdown fences, no preamble, raw JSON only)
  • Self-verification instructions
• translateLyrics prompt restructured with XML-bounded <task>, <rules>, <format>, <lyrics> sections
• AiResponseCleaner utility added for robust JSON/text response cleaning (strip markdown fences, trim whitespace, normalize newlines)
• AiPlaylistGenerator and UserProfileDigestGenerator updated to use AiResponseCleaner

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What's Removed

• DeepSeekAiClient.kt, GroqAiClient.kt, MistralAiClient.kt — unified into GenericOpenAiClient (these are all OpenAI-compatible APIs with identical request/response shapes)
• AiMetadataGenerator.kt — full file deletion
• All generateAiMetadata calls removed from: AiStateHolder, PlayerViewModel, PlayerUiState, SongInfoBottomSheet, DailyMixSection, UnifiedPlayerOverlaysLayer, DailyMixScreen, AlbumDetailScreen, ArtistDetailScreen, GenreDetailScreen, LibraryScreen, PlaylistDetailScreen, RecentlyPlayedScreen, SearchScreen, PlayerViewModelTest

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Bug Fixes

• AiHandler.kt — local function callWithModel not marked suspend (CI compilation error)
• SettingsCategoryScreen.kt — customBaseUrl StateFlow passed where String expected; now collected via collectAsStateWithLifecycle()
• GeminiAiClient — removed encodeDefaults = true from Json config to prevent serializing null fields
• AiWorker — digest generator now uses AiResponseCleaner for robust parsing

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Files Changed (37 files, +1054 / −1016)

Added

File	Description
data/ai/AiResponseCleaner.kt	Response clean/parse utility
data/ai/provider/UnifiedModelFilter.kt	Consistent model filtering across providers
presentation/screens/SettingsComponents.kt	SearchableModelSelector composable

Deleted

File	Description
data/ai/AiMetadataGenerator.kt	Metadata generation feature
data/ai/provider/DeepSeekAiClient.kt	Unified into GenericOpenAiClient
data/ai/provider/GroqAiClient.kt	Unified into GenericOpenAiClient
data/ai/provider/MistralAiClient.kt	Unified into GenericOpenAiClient

Modified (key files)

File	Key Changes
data/ai/AiHandler.kt	Fix suspend, gen params passthrough, usage tracking
data/ai/AiSystemPromptEngine.kt	CoT, few-shot, quality rails
data/ai/AiPlaylistGenerator.kt	Use AiResponseCleaner
data/ai/UserProfileDigestGenerator.kt	Use AiResponseCleaner
data/ai/provider/AiClient.kt	+6 gen param interface methods
data/ai/provider/AiClientFactory.kt	OLLAMA + CUSTOM creation
data/ai/provider/AiProvider.kt	OLLAMA + CUSTOM enum entries
data/ai/provider/GeminiAiClient.kt	Gen params, fix Json config
data/ai/provider/GenericOpenAiClient.kt	Gen params in request
data/preferences/AiPreferencesRepository.kt	+10 new preference keys
data/worker/AiWorker.kt	AiResponseCleaner usage
presentation/screens/SettingsCategoryScreen.kt	Gen params, song config, base URL sections; fix customBaseUrl
presentation/viewmodel/SettingsViewModel.kt	+10 new flows/handlers
presentation/viewmodel/AiStateHolder.kt	Remove metadata, improve translate prompt
presentation/viewmodel/PlayerViewModel.kt	Remove metadata
presentation/viewmodel/PlayerUiState.kt	Remove metadata state
presentation/components/SongInfoBottomSheet.kt	Remove metadata
10 screen/component files	Remove generateAiMetadata calls
presentation/viewmodel/PlayerViewModelTest.kt	Remove metadata test refs

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Testing

• PlayerViewModelTest.kt updated — metadata test references removed
• All changes are source-level only; existing behavior preserved for remaining AI features (playlist generation, lyrics translation, digest generation)