Stream AI responses for analyze and ask

[itsflaid]

Summary

• stream Groq chat completions for human-readable analyze and ask output
• preserve readable terminal Markdown by rendering completed paragraphs
• reconstruct complete responses for snapshots, caching, model metadata, and token usage
• keep JSON mode buffered as one machine-readable document
• document streaming behavior and maintainer test flows

Verification

• pnpm test:cli (65/65)
• pnpm build:cli
• pnpm build:web
• pnpm test:package-e2e
• git diff --check
• secret scan

Closes #19