fix: add HF Spaces README config

fix: bypass YouTube bot detection on HF Spaces

feat: controlled instrument toggle, drag-to-seek, global key anchoring

chore: add Dockerfile for HF Spaces deploy, CORS env var support

feat: 7 UI/UX improvements — BPM, waveform, chord chart, fret hints, confidence opacity, consistent key badge, 3-octave piano

Revert "feat: auto-detect guitar/keyboard from title keywords + key + spectral features"

feat: auto-detect guitar/keyboard from title keywords + key + spectral features

feat: show song title from YouTube metadata

fix: add nnAudio dependency for MERT feature_extractor_cqt

fix: auto-load .env for HF_TOKEN, add .env to gitignore

feat: audio playback with moving playhead, auto segment tracking, click-to-seek

feat: 30s timeline bars, stagger animation, fix use_return_dict deprecation, suppress audioread warning

fix: resample audio to MERT processor's 24kHz before encoding

feat: YouTube URL support + fix Tailwind v4 CSS + fix CORS ports

fix: correct confidence averaging in merge_segments, add 50MB upload limit

feat: FastAPI /analyze — MERT boundaries + KS key detection + guitar info

feat: smoother — majority-vote window smoothing + consecutive segment merger

feat: key detector — Krumhansl-Schmuckler 24-key Pearson correlation

feat: MERT boundary detector — cosine novelty curve + Gaussian smoothing

feat: MERT encoder — HuggingFace m-a-p/MERT-v1-95M, 768-dim embeddings per chunk

feat: chromagram extractor — chroma CQT mean, L1-normalized

feat: audio loader — load bytes, resample 22050 Hz mono, chunk with overlap

feat: music theory utils — scale notes, pentatonic, fretboard positions

chore: backend project scaffold with dependencies