Implement useStreaming hook for chat responses

[randomm]

Phase 3 of Ink TUI Rewrite

Objective

Create React hook that handles streaming chat responses.

Tasks

• Create src/cli/ink/hooks/useStreaming.ts
• Implement message sending
• Implement SSE stream parsing
• Handle text delta accumulation
• Implement cancel functionality
• Handle errors gracefully

Acceptance Criteria

• Messages send successfully
• Streaming text appears incrementally
• Cancel works during streaming
• Errors display appropriately
• Input disabled during streaming

Estimated: 1.5 days

[randomm]

Completed - useStreaming hook merged to dev