* Python: Fix Magentic manager duplicating conversation history
_complete() reused one persistent AgentSession, so the default history provider
re-injected prior turns on top of the full prompt the manager already rebuilds
each call — duplicating task/facts/plan and compounding every round. Use a fresh
session per call; keep self._session only for
checkpointing. GroupChatOrchestrator is unaffected. Add a regression test and
update the session-propagation test.
* Python: Clean up Magentic manager per Copilot review (drop dead _session)
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Co-authored-by: Evan Mattson <35585003+moonbox3@users.noreply.github.com>
Hasan Ghomi
f1ba16e3fd