Python: [BREAKING] Scope provider state by source_id and standardize source IDs (#3995)

* Initial plan

* Add FoundryMemoryProvider and tests

Co-authored-by: eavanvalkenburg <13749212+eavanvalkenburg@users.noreply.github.com>

* Add sample and documentation for FoundryMemoryProvider

Co-authored-by: eavanvalkenburg <13749212+eavanvalkenburg@users.noreply.github.com>

* Address code review feedback for FoundryMemoryProvider

Co-authored-by: eavanvalkenburg <13749212+eavanvalkenburg@users.noreply.github.com>

* Address PR review comments: Add DEFAULT_SOURCE_ID, use logging.getLogger, move state to session.state

Co-authored-by: eavanvalkenburg <13749212+eavanvalkenburg@users.noreply.github.com>

* Fix Foundry memory ItemParam usage and exports

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Refactor provider hook state and standardize source IDs

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Support endpoint-based Foundry memory init

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Fix core README workflows link

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* updated implementation and sample

* Split out Foundry memory provider changes

Remove FoundryMemoryProvider implementation/tests/sample plus export and docs mentions from this branch so only non-Foundry changes remain.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Trigger CI rerun for PR #3995

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---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: eavanvalkenburg <13749212+eavanvalkenburg@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

python/samples/02-agents/chat_client/custom_chat_client.py

@@ -13,6 +13,7 @@ from agent_framework import (
     ChatResponseUpdate,
     Content,
     FunctionInvocationLayer,
+    InMemoryHistoryProvider,
     Message,
     ResponseStream,
 )
@@ -195,7 +196,7 @@ async def main() -> None:
         print(f"Agent: {result.messages[0].text}\n")
 
     # Check conversation history
-    memory_state = session.state.get("memory", {})
+    memory_state = session.state.get(InMemoryHistoryProvider.DEFAULT_SOURCE_ID, {})
     session_messages = memory_state.get("messages", [])
     if session_messages:
         print(f"Session contains {len(session_messages)} messages")