fix: add GPT-5 and o-series to multimodal vision prefixes (#5183)

* fix: add GPT-5, o3, o4-mini to multimodal vision prefixes

Added verified vision-capable models:
- gpt-5 (all GPT-5 family — confirmed multimodal via openai.com)
- o3, o3-pro (full multimodal — openai.com/index/thinking-with-images)
- o4-mini, o4 (full multimodal)

Added text-only exclusion list to prevent false positives:
- o3-mini (text-only, replaced by o4-mini)
- o1-mini (text-only)
- o1-preview (text-only)

Existing prefixes unchanged (Claude 3+, Gemini, GPT-4).

* fix: add o1 to vision prefixes + ruff format

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix: guard _sync_executor access in test utils for lazy-init event bus

* fix: expand vision model coverage — Claude 5, Grok, Pixtral, Qwen VL, LLaVA

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* ci: retrigger — flaky test_hierarchical_verbose_false_manager_agent (ConnectionError)

* fix: remove hallucinated claude-5 models from vision prefixes — verified against official docs

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

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Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Co-authored-by: João Moura <joaomdmoura@gmail.com>