[auto-change] BUG-036: Echoes public-source intake smoke run fails on empty LLM response

[Jonnyton]

Fixes #81

Writer family: Codex
Required checker family: Claude

Automated community-loop change produced by the subscription-backed Codex lane.

[Jonnyton]

Loop review policy

• Writer family: Codex
• Required checker family: Claude

Do not accept this PR with a same-family checker.

[Jonnyton]

Codex key: HOLD / revision required.

The direction is right: empty provider text should not be treated as successful LLM output, and falling through from an empty API provider to a usable fallback is valuable. But the implementation still has a gap: in ProviderRouter.call, when a local provider returns empty text and all_api_providers_in_cooldown(...) is false, control falls through to the "Successful call" block and returns the empty local response. That can happen when API providers are absent/not registered rather than explicitly cooled down, which is a common daemon shape.

Please add a regression test for local-only / missing-API registry returning empty text, and make every empty response either continue to another provider or fail loudly with diagnostics. After that, this should be mergeable.

[Jonnyton]

Auto-change PR closed as superseded

This stale-base PR from auto-change/issue-81-codex-25417406236 was superseded by #708 from auto-change/issue-81-codex-25580949514.
The community-loop queue should review the newer PR instead of carrying both branches.