.NET: Python: Add AGENTS.md files and update coding standards (#3644)

* Add AGENTS.md files and update coding standards for Python

- Add root python/AGENTS.md with project structure and package links
- Add AGENTS.md for each package describing purpose and main classes
- Update .github/copilot-instructions.md with improved structure
- Update python/CODING_STANDARD.md with API review guidance:
  - Future annotations convention (#3578)
  - TypeVar naming convention (#3594)
  - Mapping vs MutableMapping (#3577)
  - Avoid shadowing built-ins (#3583)
  - Explicit exports (#3605)
  - Exception documentation guidelines (#3410)
- Simplify python/.github/instructions/python.instructions.md to reference AGENTS.md
- Remove AGENTS.md from .gitignore

* Fix purview import path in AGENTS.md

* Address PR review comments and restructure instructions

- Slim down .github/copilot-instructions.md to reference language-specific docs
- Add ADR section explaining templates and purpose
- Create dotnet/AGENTS.md with .NET-specific build commands, conventions, and sample guidance
- Update Python build/test instructions for core vs isolated changes
- Fix Microsoft.Extensions.AI package references
- Update kwargs guidance per issue #3642
- Fix Python sample helper placement (top, not bottom)
- Document new 'typing' poe task in DEV_SETUP.md

* Add 'typing' poe task to run both pyright and mypy

* Add kwargs guidelines from issue #3642 to CODING_STANDARD.md

* Clarify that connector packages pull in core as dependency

python/packages/durabletask/AGENTS.md

@@ -0,0 +1,46 @@
+# Durable Task Package (agent-framework-durabletask)
+
+Durable execution support for long-running agent workflows using Azure Durable Functions.
+
+## Main Classes
+
+### Client Side
+
+- **`DurableAIAgentClient`** - Client for invoking durable agents
+- **`DurableAIAgent`** - Shim for creating durable agents
+
+### Worker Side
+
+- **`DurableAIAgentWorker`** - Worker that executes durable agent tasks
+- **`DurableAgentExecutor`** - Executes agent logic within durable context
+- **`AgentEntity`** - Durable entity for agent state management
+
+### State Management
+
+- **`DurableAgentState`** - State container for durable agents
+- **`DurableAgentThread`** - Thread management for durable agents
+- **`DurableAIAgentOrchestrationContext`** - Orchestration context
+
+### Callbacks
+
+- **`AgentCallbackContext`** - Context for agent callbacks
+- **`AgentResponseCallbackProtocol`** - Protocol for response callbacks
+
+## Usage
+
+```python
+from agent_framework_durabletask import DurableAIAgentClient, DurableAIAgentWorker
+
+# Client side
+client = DurableAIAgentClient(endpoint="https://your-functions.azurewebsites.net")
+response = await client.run("Hello")
+
+# Worker side
+worker = DurableAIAgentWorker(agent=my_agent)
+```
+
+## Import Path
+
+```python
+from agent_framework_durabletask import DurableAIAgentClient, DurableAIAgentWorker
+```