Add schema versioning documentation to README

Added comprehensive documentation about the annotation schema versioning system:
- Current schema version (1.0.0) with release date
- Semantic versioning explanation (MAJOR.MINOR.PATCH)
- Schema evolution benefits (tracking, compatibility, migration)
- Complete schema coverage breakdown:
- 31 classification categories
- 10 audio defect types
- 5 content issue types
- 7 supported languages
- 5 transcription quality levels
- Updated data organization tree to include schema/ directory
- References to schema documentation files (README, CHANGELOG)

This makes the dataset's annotation methodology transparent and helps
users understand how annotations may evolve over time.

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

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

README.md

@@ -67,9 +67,12 @@ Voice-Note-Audio/
 │   ├── uncorrected/               # AI-generated transcripts from STT
 │   └── ground_truths/             # Manually corrected transcripts
 ├── annotations/                    # JSON metadata for each recording
+├── schema/                         # Annotation schema (versioned)
+│   ├── annotation_schema_v1.json  # Schema definition v1.0.0
+│   ├── README.md                  # Schema documentation
+│   └── CHANGELOG.md               # Version history
 ├── STATS.md                       # Auto-generated dataset statistics
-├── ANNOTATION_SCHEMA.md           # Detailed schema documentation
-└── annotation_schema_v1.json      # JSON schema specification
+└── README.md                      # This file
 ```
 
 Files are numbered sequentially (e.g., `1.mp3`, `1.txt`, `1.json`) for easy cross-referencing.
@@ -105,31 +108,69 @@ Study code-switching and multilingual speech patterns in authentic voice recordi
 
 ## Annotation Schema
 
-The dataset uses a comprehensive annotation schema covering:
-
-### Audio Quality Indicators
-- Quality ratings: Clear, Good, Fair, Poor, Very Poor
-- Noise types: Traffic, conversations, music, wind, office noise, crying baby
-- Audio challenges and environmental factors
-
-### Content & Context
-- Note type classification (8+ categories)
-- Recording location and environment
-- Multi-language indicators
-- Time-of-day metadata
-
-### Technical Specifications
-- Microphone types (OnePlus Nord 3 Internal, Poly 5200, ATR 4697, etc.)
-- Bluetooth codecs (SBC, AAC, aptX, aptX HD, LDAC, LC3)
-- Audio format and encoding details
-
-### Text Analysis
-- Word count and character count metrics
-- Lexical diversity measurements
-- Speaking rate (WPM) calculations
-- Sentence structure analysis
-
-See `ANNOTATION_SCHEMA.md` for complete schema documentation.
+The dataset uses a comprehensive, versioned annotation schema to ensure consistency and enable schema evolution over time.
+
+**Current Schema Version: 1.0.0** (Released: 2025-10-26)
+
+### Schema Versioning
+
+The annotation schema follows [Semantic Versioning](https://semver.org/) (MAJOR.MINOR.PATCH):
+- **MAJOR**: Incompatible schema changes
+- **MINOR**: Backward-compatible additions
+- **PATCH**: Backward-compatible bug fixes
+
+Each annotation automatically includes a `schema_version` field, enabling:
+- Tracking which schema version was used for each annotation
+- Backward compatibility as the schema evolves
+- Migration paths when schema updates occur
+- Historical analysis of annotation practices
+
+Schema files and documentation are maintained in the `schema/` directory:
+- `annotation_schema_v1.json` - Current schema definition
+- `README.md` - Schema usage and documentation
+- `CHANGELOG.md` - Version history and changes
+
+### Schema Coverage
+
+#### Classification (31 categories)
+Comprehensive note type classification including:
+- **Communication**: Email drafts, replies
+- **Task Management**: To-do lists, reminders, shopping lists
+- **Content Creation**: Blog posts, articles, social media, scripts, presentations
+- **Development**: Prompts (general, development, creative), documentation, code comments, bug reports, feature requests
+- **Personal & Professional**: Journal entries, memos, ideas, meeting notes, research notes, project planning
+- **General**: Questions, other
+
+#### Audio Defects (10 categories)
+Real-world audio challenges for STT evaluation:
+- Background noise, music, conversations
+- Crying baby, traffic sounds
+- Poor quality (distortion, clipping)
+- Multiple speakers, wind noise, echo
+- Phone ringing/notifications
+
+#### Content Issues (5 categories)
+Recording-level problems:
+- Side conversations, partial content
+- False starts, thinking aloud
+- Self-correction during recording
+
+#### Languages (7 supported)
+Multi-language support for:
+- English, Hebrew, Arabic
+- Russian, French, Spanish, German
+
+#### Transcription Quality (5 levels)
+STT output assessment:
+- Excellent, Good, Fair, Poor, Unusable
+
+#### Additional Metadata
+- **Audio Quality Indicators**: Quality ratings, noise types, environmental factors
+- **Technical Specifications**: Microphone types, Bluetooth codecs, audio formats
+- **Text Analysis**: Word/character counts, lexical diversity, speaking rate (WPM)
+- **Context**: Recording location, time of day, multi-language indicators
+
+See `schema/README.md` and `schema/CHANGELOG.md` for complete schema documentation and version history.
 
 ## Recording Equipment