[Python] Restore final beta compatibility fixes

[Chris Gillum (cgillum)]

Why

The durable extension repository was extracted before the final Python 1.13.0 beta publishing cut. As a result, the public agent-framework-durabletask==1.0.0b260730 and agent-framework-azurefunctions==1.0.0b260730 include two package-specific compatibility changes that are absent here.

This PR restores those changes directly against main. It is independent of PR #58 and does not use its package-version changes.

What changes

Capturing runner contexts now reject checkpoint construction explicitly. This preserves the activity-context contract with newer Agent Framework Core releases instead of inheriting a protocol stub that returns None.

Durable Task and Azure Functions now mark their final-beta feature indexes at the same activation points used by the published packages. This lets Agent Framework Core include feature usage in User-Agent telemetry.

Both packages now require agent-framework-core>=1.13.0,<2. The lock resolves Core 1.16 and its msgspec dependency, while Azure Functions keeps its existing agent-framework-durabletask>=1.0.0b260709,<2 dependency.

Compatibility

• Restores behavior shipped in the final public beta packages.
• Keeps current package versions and the existing Azure Functions-to-Durable Task beta dependency unchanged.
• Adds no dependency on PR Prepare durable extension RC package versions #58.

Review focus

Please verify that the checkpoint failure behavior and feature activation points match the final beta contract, and that the lockfile change is limited to the required Core floor and transitive dependency.

[Copilot]

Pull request overview

Restores Python durable-extension behaviors that shipped in the last published beta packages by (1) explicitly rejecting checkpoint construction in activity runner contexts, (2) emitting Agent Framework Core feature-usage telemetry at the intended activation points, and (3) aligning both Python packages’ Core dependency floor to >=1.13.0,<2 (with corresponding lock refresh).

Changes:

• Add explicit build_checkpoint(...) NotImplementedError overrides to capturing runner contexts (Durable Task + Azure Functions) and corresponding tests.
• Add per-package FeatureIndex enums and call mark_feature_used(...) from key entrypoints, with tests validating the feature index activation.
• Raise agent-framework-core minimum version to 1.13.0 in both packages and update uv.lock to resolve a newer Core (1.16.0) plus transitive deps.

Reviewed changes

Copilot reviewed 14 out of 15 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
python/uv.lock	Updates Core floor and resolved versions; adds msgspec as a transitive dependency.
python/packages/durabletask/pyproject.toml	Bumps agent-framework-core requirement to >=1.13.0,<2.
python/packages/azurefunctions/pyproject.toml	Bumps agent-framework-core requirement to >=1.13.0,<2.
python/packages/durabletask/agent_framework_durabletask/_workflows/runner_context.py	Adds explicit build_checkpoint rejection for activity context.
python/packages/azurefunctions/agent_framework_azurefunctions/_context.py	Adds explicit build_checkpoint rejection for activity context.
python/packages/durabletask/agent_framework_durabletask/_worker.py	Marks Durable Task feature usage when the worker starts.
python/packages/durabletask/agent_framework_durabletask/_shim.py	Marks Durable Task feature usage when the shim run() is invoked.
python/packages/azurefunctions/agent_framework_azurefunctions/_app.py	Marks Azure Functions feature usage during app initialization.
python/packages/durabletask/agent_framework_durabletask/_feature_usage.py	Introduces Durable Task feature index enum.
python/packages/azurefunctions/agent_framework_azurefunctions/_feature_usage.py	Introduces Azure Functions feature index enum.
python/packages/durabletask/tests/test_worker.py	Verifies worker start triggers feature usage marking.
python/packages/durabletask/tests/test_shim.py	Verifies shim run triggers feature usage marking.
python/packages/durabletask/tests/test_runner_context.py	Adds coverage for build_checkpoint raising in Durable Task capturing context.
python/packages/azurefunctions/tests/test_func_utils.py	Adds coverage for build_checkpoint raising in Azure Functions capturing context.
python/packages/azurefunctions/tests/test_app.py	Verifies app init triggers feature usage marking.

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[Copilot]

Pull request overview

Copilot reviewed 15 out of 16 changed files in this pull request and generated no new comments.