v0.6.8

• Delete update-changelog.yml by @pushpak1300 in #525
• Add error handling tests for VoyageAI reranking by @mosabbirrakib in #527
• Add error handling tests for OpenAI image generation by @mosabbirrakib in #528
• Add error handling tests for VoyageAI embeddings by @mosabbirrakib in #526
• Handle Anthropic pause_turn server-tool continuations by @CodeWrap in #493
• Add sub-agent support as tools by @JVillator0 in #348
• Make conversation/message table names configurable by @timmcleod in #484
• Add error handling tests for image generation (Gemini, AzureOpenAI, OpenRouter) by @mdalikadar in #545
• Add rate limit and overloaded error tests for ElevenLabs audio by @mosabbirrakib in #542
• Add rate limit and overloaded error tests for Cohere reranking by @mosabbirrakib in #540
• Add rate limit and overloaded error tests for Jina reranking by @mosabbirrakib in #541
• Add tests for Gemini image generation safety blocks by @mosabbirrakib in #547
• Add error handling tests for embeddings (OpenAI, Gemini) by @mdalikadar in #546
• Fix parameter name in GeneratesEmbeddings PHPDoc by @mosabbirrakib in #549
• Remove stale @param and unused Request import in Vercel protocol trait by @mosabbirrakib in #551
• Fix nonexistent ImageAttachment type in image-related PHPDoc by @mosabbirrakib in #550
• Add error handling tests for AzureOpenAI image generation by @mosabbirrakib in #537
• Mark nullable size and quality docblocks across image gateways by @mosabbirrakib in #552
• Broadcast stream_failed event when BroadcastAgent job fails by @sumaiazaman in #536
• Gemini context cache support via cachedContent param in agent provider options by @dumbbellcode in #556
• Fix: DeepSeek 400 Bad Request on multi-turn tool-calls by preserving reasoning_content by @k1rana in #534
• OpenRouter TTS and STT support by @ondrejehrlich in #559
• Support provider options in embeddings by @dumbbellcode in #555
• Enable failover during stream iteration by @kachelle in #279