Migration guides rely on AgentKit CLI commands absent from public releases

### Description

The migration guides document `agentkit migrate` and `agentkit release` as required public workflow steps, but neither command is registered by the released AgentKit CLI used by these samples.

Across `python/03-integrations/migration`, the tracked documentation contains 36 `agentkit migrate` invocations and 20 `agentkit release` invocations. The affected guides include the Strands, AgentCore, LangChain, Dify, and generic migration flows in both available language variants.

### Reproduction

At commit `0890278a6571e4190c1ab8cacd9becc147f74d9c`, the migration projects require `agentkit-sdk-python>=0.7.12`. The latest public package available at audit time was 0.8.4.

```powershell
uvx --from agentkit-sdk-python==0.8.4 agentkit --help
uvx --from agentkit-sdk-python==0.8.4 agentkit migrate --help
uvx --from agentkit-sdk-python==0.8.4 agentkit release --help
```

`--help` does not list either command, and both direct invocations fail with `No such command`.

A representative documented entry point is `python/03-integrations/migration/strands/README_en.md`, where migration starts with `agentkit migrate` and deployment later uses `agentkit release`.

### Expected behavior

Every documented migration and release command should be available in the public package/runtime version required by the sample, or the guides should identify an explicit preview package/channel and its installation/version requirements.

### Impact

Users following any of these migration guides are blocked at the core migration or release step, before they can validate the generated AgentKit project.

### Duplicate check

Open and closed issues, all PR states, repository discussions, relevant file history, and default-branch commits were searched using both command names and migration-guide terms. No equivalent report or fix was found. Discussions are disabled for this repository.

### Why there is no PR in this audit

The repository does not expose the intended replacement command, preview package, or release schedule. Choosing between renaming commands, pinning an unpublished channel, or removing the feature requires a maintainer product/release decision; changing all localized guides speculatively would risk documenting another invalid workflow.

Start with python/03-integrations/migration/strands/README_en.md and search the migration directory for all `agentkit migrate` and `agentkit release` uses. Run the reported AgentKit 0.8.4 help commands to verify the public CLI, then review the affected language variants. Done means the guides consistently describe a publicly available workflow or explicitly document the required preview package and version.

Written by the indexing model from the issue text.