Function diverge

diverge(opts: DivergeOptions): Operation<DivergeResult>
Multi-branch perplexity selection as an Effection operation

Forks N branches from a parent (or a fresh root), generates to EOG via batched BranchStore.commit, then selects the lowest-perplexity attempt. Loser branches are pruned; the caller receives the best branch still alive.

When opts.parent is provided, the parent branch is NOT pruned — it's owned by the calling scope. Only the forked attempt branches (losers) are pruned. The caller owns the winning branch's lifecycle, typically via Session.promote.

Cleanup is structured: each forked branch registers an ensure() callback that prunes it on scope exit. Winners are marked disposed-safe (already pruned or ownership transferred) before the ensure fires.
Parameters
- opts: DivergeOptions
  Diverge options specifying parent or prompt, attempt count, and sampling parameters
Returns Operation<DivergeResult>
Result containing the best branch, all attempt outputs, and aggregate statistics
Example: Verify with perplexity selection
```
const verified = yield* diverge({
  prompt: verifyPrompt,
  attempts: 3,
  params: { temperature: 0.7 },
});
// verified.best is the lowest-perplexity branch, still alive
yield* call(() => session.promote(verified.best));
```
- Defined in agents/src/diverge.ts:43