Python: Add Mistral AI embedding client package (#5480)

* Python: Add Mistral AI embedding client package

Signed-off-by: Daria Korenieva <daric2612@gmail.com>

* Address review feedback: fix dimensions check, sort embeddings by index, align docs

Signed-off-by: Daria Korenieva <daric2612@gmail.com>

* Address review feedback: downgrade to alpha, remove integration tests - Change version to 1.0.0a260505 (alpha) - Update classifier to Development Status :: 3 - Alpha - Update PACKAGE_STATUS.md to alpha - Remove Mistral from integration test workflows (no API keys yet)

Signed-off-by: Daria Korenieva <daric2612@gmail.com>

* Add samples directory for alpha package compliance Per python-package-management skill: alpha packages must include samples inside the package directory.

Signed-off-by: Daria Korenieva <daric2612@gmail.com>

* Fix ruff formatting in sample file

Signed-off-by: Daria Korenieva <daric2612@gmail.com>

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Signed-off-by: Daria Korenieva <daric2612@gmail.com>

python/packages/mistral/AGENTS.md

@@ -0,0 +1,26 @@
+# Mistral Package (agent-framework-mistral)
+
+Integration with Mistral AI for embedding generation.
+
+## Main Classes
+
+- **`MistralEmbeddingClient`** - Embedding client for Mistral AI models
+- **`MistralEmbeddingOptions`** - Options TypedDict for Mistral-specific embedding parameters
+- **`MistralEmbeddingSettings`** - TypedDict settings for Mistral configuration
+
+## Usage
+
+```python
+from agent_framework_mistral import MistralEmbeddingClient
+
+# Requires MISTRAL_API_KEY environment variable (or pass api_key= directly)
+client = MistralEmbeddingClient(model="mistral-embed")
+result = await client.get_embeddings(["Hello, world!"])
+print(result[0].vector)
+```
+
+## Import Path
+
+```python
+from agent_framework_mistral import MistralEmbeddingClient
+```