HSI 1.0 Export Capability: synheart-core-dart can now export HSI 1.0 canonical payloads

• New HSI10Payload class matching canonical HSI 1.0 schema
• toHSI10() extension method on HumanStateVector
• Converts internal HSV representation to external HSI 1.0 contract format
• Full JSON Schema compliance with /hsi/schema/hsi-1.0.schema.json
• Producer metadata (name, version, instance_id)
• Window-based time scoping (micro/short/medium/long)
• Privacy-compliant assertions (no PII, derived metrics only)
• Comprehensive test suite (16 tests) validating HSI 1.0 compliance

HSV State Axes: Implemented core HSV (Human State Vector) state representation axes

• Added AffectAxis (arousalIndex, valenceStability)
• Added EngagementAxis (engagementStability, interactionCadence)
• Added ActivityAxis (motionIndex, postureStability)
• Added ContextAxis (screenActiveRatio, sessionFragmentation)
• Added StateEmbedding class for 64D dense vector representation
• Added HSIAxes container class grouping all state axes

HSV Computation in FusionEngine: Enhanced fusion engine to compute HSV state axes

• Computes arousal index from HR and HRV (60% HR, 40% HRV inverse)
• Computes valence stability from HRV SDNN
• Computes engagement stability and interaction cadence from behavioral patterns
• Computes motion index from wear and phone sensors
• Computes screen active ratio and session fragmentation from context
• All indices normalized to [0.0, 1.0] range with null for missing signals

Interpretation Modules: Both EmotionHead and FocusHead properly integrated

• EmotionHead uses EmotionEngine from synheart-emotion package
• FocusHead uses FocusEngine from synheart-focus package
• Both consume HSI state representation and produce semantic interpretations

Comprehensive test suite for EmotionHead module

• Tests for EmotionEngine initialization
• Tests for push/consumeReady API pattern
• Tests for EmotionResult to EmotionState mapping
• Tests for graceful handling of invalid/missing data
• Tests for lifecycle management (start, stop, dispose)

EmotionHead: Refactored to use EmotionEngine from synheart-emotion package instead of direct ONNX model access

• Now uses EmotionEngine.fromPretrained() for initialization
• Changed from async predictAsync() to synchronous push/consumeReady pattern
• Implements proper time-series emotion detection with ring buffer (10s window, 1s step)
• Synthesizes RR intervals from derived HRV features (temporary workaround until Phase 2 adds raw RR data to HSV)
• Improved cleanup logic to call engine.clear() on dispose

MetaState: Updated to include HSI state axes and proper embedding structure

• Replaced hsiEmbedding List
• Added HSIAxes axes field containing all state representation axes
• Maintains backward compatibility through factory constructors

HumanStateVector (HSV): Enhanced to support full HSV state representation

• Includes state axes (affect, engagement, activity, context)
• Includes 64D state embedding
• Supports window types (micro, short, medium, long)
• Provides structured, interpretation-agnostic state representation
• Can export to HSI 1.0 canonical format via toHSI10() method

Hybrid Approach: HSV (language-agnostic model) + HSI 1.0 (cross-platform format)

• HSV (Human State Vector): Language-agnostic state model implemented in Dart classes
  • Same conceptual model across all platforms (Dart, Kotlin, Swift)
  • Fast, type-safe on-device processing
• HSI 1.0 (Human State Interface): Cross-platform JSON wire format
  • Platform-agnostic canonical format for interoperability
• Best of both worlds: native performance, cross-platform compliance

Public API: removed legacy HSI entrypoints; Synheart is now the single SDK entrypoint exported from package:synheart_core/synheart_core.dart.

Logging: replaced print() usage with internal logger to satisfy flutter_lints (avoid_print).

Examples: cleaned up naming and flow to match Synheart (including renaming the full pipeline demo).

• synheart_emotion: ^0.2.2
• synheart_focus: ^0.0.1
• synheart_wear: ^0.1.2