[Option B] Consolidate SyncPullStrategy implementation

[danieljsinclair]

Issue

Consolidate SyncPullAudioMode + SyncPullRenderer into unified SyncPullStrategy.

Background

Current architecture has coupled pair that cannot be swapped independently:

• SyncPullAudioMode: Handles lifecycle and simulation updates
• SyncPullRenderer: Handles on-demand rendering

This creates unnecessary complexity and violates OCP.

Goal

Create SyncPullStrategy that unifies lifecycle and rendering:

• Single class implementing IAudioStrategy
• Uses IAudioHardwareProvider for platform-specific audio
• Handles on-demand rendering internally
• No buffering (direct callback to bridge API)

Implementation Plan

1. Create SyncPullStrategy.h/cpp implementing IAudioStrategy
2. Merge SyncPullAudioMode lifecycle methods into SyncPullStrategy
3. Merge SyncPullRenderer rendering methods into SyncPullStrategy
4. Inject IAudioHardwareProvider instead of using AudioUnit directly
5. Implement on-demand rendering (call bridge RenderOnDemand in callback)
6. Maintain sync-pull diagnostics (timing, budget tracking)

Acceptance Criteria

1. SyncPullStrategy.h/cpp created implementing IAudioStrategy
2. Combines SyncPullAudioMode + SyncPullRenderer functionality
3. Uses IAudioHardwareProvider for audio hardware access
4. Maintains all sync-pull behavior (on-demand rendering, diagnostics)
5. All tests pass (existing SyncPullRenderer tests)
6. Clean build with no warnings

Testing

• All existing SyncPullRenderer unit tests pass
• All existing SyncPullAudioMode unit tests pass
• Simulator-level audio tests produce identical output
• No behavioral changes (audio sounds identical)

Dependencies

• CRITICAL: Documentation describes non-existent NEW architecture (IAudioStrategy) #8: Create IAudioStrategy interface
• Remove/accurately document SilentRenderer in architecture docs #9: Create IAudioHardwareProvider interface
• Document actual pull model architecture (modes/renderers/factories) #11: Create CoreAudioHardwareProvider implementation

Related Issues

• Clarify FillSilence location in architecture documentation #10: Consolidate ThreadedStrategy implementation
• Archive and reference historical investigation docs #14: Update CLIMain wiring for IAudioStrategy