Can I vibecode YouTube Music Premium?

Build a highly functional, beautifully designed personal substitute for YouTube Music Premium in an empty repository. 
Use precisely this stack: Python 3.12, FastAPI, SQLite, ffmpeg, and a modern local web interface (e.g., React or Vue, strictly compiled to static assets served by FastAPI); do not offer alternative stacks.

Primary Objective: Create an ad-free, private, locally hosted music streaming platform to organize, stream, and manage legally owned or user-created audio files. It must provide a premium playback experience akin to YouTube Music Premium, strictly without accessing YouTube's licensed catalog.

Detailed Feature Requirements:
1. Uninterrupted, Ad-Free Playback: Ensure a seamless listening experience for large local libraries (100k+ songs). Implement gapless playback and robust streaming of high-quality audio formats (FLAC, 320kbps MP3/AAC) directly to the browser.
2. Background Play & Audio-Only Focus: Design the web UI as a Progressive Web App (PWA) with Media Session API support so playback continues smoothly in the background, even on mobile devices when the screen is locked or the user switches tabs. 
3. Offline Downloads & Smart Syncing: Implement a mechanism in the PWA to download selected albums, playlists, or favorite tracks directly to the browser's local storage or IndexedDB for true offline listening without needing the server connection.
4. Smart Playlists & Recommendations: Build a lightweight local recommendation engine that generates "Mixes" (e.g., "Discover Mix," "New Release Mix" based on newly added local files) and smart playlists based on listening history, play counts, and audio tags.
5. Rich Metadata & Organization: Deeply index user-selected folders. Read ID3 tags, extract embedded artwork, calculate ReplayGain/loudness, generate waveform data for visual scrubbing, and detect exact duplicates by file hash. Support albums, artists, genres, and manual playlist creation.
6. Creator & Editing Tools: Add optional tools using `ffmpeg` to trim audio, normalize volume, and theoretically split stems (using a local model if provided), allowing export of the modified files.

Strict Constraints:
- Make the first run work locally with one single, heavily documented command (e.g., a simple bash script or docker-compose).
- All user data, play history, and files remain strictly local. No accounts, telemetry, analytics, or hosted control plane.
- Deliberately leave out: copyrighted catalog acquisition, streaming-service circumvention, royalty accounting, label distribution, and global content delivery. This is strictly a BYOM (Bring Your Own Music) platform.
- Put secrets in .env, ship .env.example, and gracefully handle missing optional APIs.
- Include clear empty, loading, success, and error states. 
- Write focused unit tests for the audio indexing and transformation logic, plus an end-to-end happy path test. 
- Output the commands used to run tests and ensure they pass before completing.