providers: implement BedrockProvider via Converse API

Quality drive: schema fix, 5 new/revised packs, 4 engine tests, scenario audit

Strip empty tool_calls from wire history (Together Qwen3.6-Plus fix)

feat(providers): SSE streaming + auto-enable for together.ai

fix(providers): wire 'together' provider through make_provider dispatch

feat(providers): add together.ai preset (Qwen3.6-Plus and friends)

Structured-fog text mode, premium routing, codex descriptions, minimap colour-by-difficulty

Live-smoke fixes: tool-call wire 400, episode resilience, real PNG minimap

Eval resilience layer for real OpenRouter runs

Playback: capture model reasoning + per-turn goal tracker + viewer

Add provider-agnostic model agent (vLLM/OpenRouter/Bedrock)