[Search] Refresh azure-search-documents samples for 2026-04-01 GA

[hizixin]

• Add sample_knowledge_source_crud(.py/_async.py) and sample_knowledge_base_crud(.py/_async.py) as CRUD reference samples.
• Refocus sample_agentic_retrieval(.py/_async.py) on the end-to-end retrieval flow (setup KS+KB, retrieve, cleanup) and cross-reference the CRUD samples for full lifecycle coverage.
• Unify sample resource naming on the hotels-sample-* convention across alias, vector profile/HNSW configs, KS, KB, semantic config, and indexer data source samples.
• Fix sample_query_vector(.py/_async.py) post-upload race by polling get_document_count before issuing the first query.

Description

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• The pull request does not introduce [breaking changes]
• CHANGELOG is updated for new features, bug fixes or other significant changes.
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Testing Guidelines

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[Copilot]

Pull request overview

This PR refreshes azure-search-documents Python samples for the 2026-04-01 GA surface area, expanding agentic retrieval coverage with dedicated Knowledge Source/Knowledge Base CRUD samples and improving consistency/reliability across sample resources.

Changes:

• Added new CRUD reference samples for Knowledge Sources and Knowledge Bases (sync + async).
• Refocused the agentic retrieval samples on an end-to-end flow (setup → retrieve → cleanup) and cross-referenced the CRUD samples for full lifecycle details.
• Updated vector query samples to reduce post-upload race conditions by polling document count before issuing the first query; standardized several resource names to the hotels-sample-* convention.

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
sdk/search/azure-search-documents/samples/sample_query_vector_async.py	Updates vector profile/HNSW naming and adds post-upload polling to mitigate first-query race.
sdk/search/azure-search-documents/samples/sample_query_vector.py	Same as async variant: naming updates + polling to mitigate first-query race.
sdk/search/azure-search-documents/samples/sample_knowledge_source_crud_async.py	New async CRUD sample for knowledge sources.
sdk/search/azure-search-documents/samples/sample_knowledge_source_crud.py	New sync CRUD sample for knowledge sources.
sdk/search/azure-search-documents/samples/sample_knowledge_base_crud_async.py	New async CRUD sample for knowledge bases.
sdk/search/azure-search-documents/samples/sample_knowledge_base_crud.py	New sync CRUD sample for knowledge bases.
sdk/search/azure-search-documents/samples/sample_indexer_datasource_crud_async.py	Aligns variable/resource naming with the hotels-sample-* convention.
sdk/search/azure-search-documents/samples/sample_indexer_datasource_crud.py	Aligns variable/resource naming with the hotels-sample-* convention.
sdk/search/azure-search-documents/samples/sample_index_alias_crud_async.py	Renames alias to hotels-sample-* naming convention.
sdk/search/azure-search-documents/samples/sample_index_alias_crud.py	Renames alias to hotels-sample-* naming convention.
sdk/search/azure-search-documents/samples/sample_agentic_retrieval_async.py	Refactors into end-to-end flow and updates retrieval client usage patterns.
sdk/search/azure-search-documents/samples/sample_agentic_retrieval.py	Refactors into end-to-end flow and updates retrieval client usage patterns.