adapters: PydanticAI TargetAdapter package #45

Problem

ROADMAP Beta lists PydanticAI alongside LangGraph/CrewAI. No package exists. Architecture supports an independent adapter (ADR-018) once tool observation is proven.

Repository evidence

• TargetAdapter port
• Reference: packages/mutiny_openai_agents/
• docs/ROADMAP.md Beta

Why it matters

PydanticAI users get the same Local CLI campaign/minimize/regress loop without Core forks. Prefer after or parallel to LangGraph (#29) — same interface.

Proposed direction

New packages/mutiny_pydantic_ai/ (name TBD) implementing TargetAdapter with offline unit fixture. Fail closed with ToolsNotObservableError if tools cannot be observed.

Acceptance criteria

• Package + README (CLI-local; Hosted observe-only)
• Offline unit test with tool observation or explicit observability error contract
• Core unchanged

Scope / NOT included

• AutoGen (v1 roadmap); Hosted exec; stub-only empty packages

Difficulty

L · adapters