feat: simplify turn API

[varin-nair-factory]

Summary

Simplifies the TypeScript SDK turn API around two paths:

• run(prompt, options?) for one-shot aggregated results
• session.send(prompt, options?) for starting a turn, then turn.stream() or turn.result()

This removes the overlapping query(...) API and DroidSession.stream(prompt, options?), and updates docs, examples, and tests to the new shape.

Closes FAC-20152: https://linear.app/factoryai/issue/FAC-20152/simplify-droid-sdk-public-session-apis

Examples

One-shot aggregate result:

import { run } from '@factory/droid-sdk';

const result = await run('Summarize this project');
console.log(result.text);

Streaming a session turn:

import { DroidMessageType, createSession } from '@factory/droid-sdk';

const session = await createSession();

try {
  const turn = await session.send('List the TypeScript files');

  for await (const msg of turn.stream()) {
    if (msg.type === DroidMessageType.AssistantTextDelta) {
      process.stdout.write(msg.text);
    }
  }
} finally {
  await session.close();
}

Aggregating a session turn:

const session = await createSession();

try {
  const turn = await session.send('Summarize this project');
  const result = await turn.result();

  console.log(result.text);
} finally {
  await session.close();
}

Notes

This is a breaking API cleanup:

• Removed query(...)
• Removed DroidSession.stream(prompt, options?)
• Changed DroidSession.send(...) to return a DroidTurn

Validation

• npm run typecheck
• npm run typecheck:examples
• npm run lint
• npm run format:check
• npm test
• npm run build