fix: skip sanity tests gracefully when optional dependencies are missing

[Wmx-5Percent]

Problem

6 sanity tests fail with ModuleNotFoundError or AttributeError when optional dependencies are not installed, rather than being gracefully skipped:

test_database_sanity.py — 5 failures:

• TestClickHouseRunner (4 methods) — clickhouse_connect not installed
• TestOracleRunner (4 methods) — oracledb not installed
• TestMSSQLRunner (4 methods) — pyodbc not installed
• TestPrestoRunner (4 methods) — pyhive not installed
• TestHiveRunner (4 methods) — pyhive not installed

test_agent_memory_sanity.py — 1 failure:

• TestFAISSAgentMemory::test_faiss_instantiation — asserts memory.persist_path but FAISSAgentMemory stores the path as self.index_path

Fix

1. Database runner tests (test_database_sanity.py)

Added try/except ImportError: pytest.skip(...) guards to all 20 test methods across the 5 affected test classes. This covers both:

• Module-level ImportError (when the integration module can't be imported)
• Constructor-level ImportError (when the Runner's __init__ checks for the underlying package)

This follows the exact same pattern already used in test_agent_memory_sanity.py for optional memory backends (ChromaDB, Qdrant, Pinecone, Milvus, Weaviate, FAISS, OpenSearch, AzureAISearch, Marqo).

2. FAISS memory test (test_agent_memory_sanity.py)

Fixed the incorrect attribute assertion: memory.persist_path → memory.index_path, matching the actual FAISSAgentMemory.__init__ which stores the path as self.index_path.

Before

FAILED tests/test_database_sanity.py::TestClickHouseRunner::test_clickhouse_runner_instantiation - ModuleNotFoundError: No module named 'clickhouse_connect'
FAILED tests/test_database_sanity.py::TestOracleRunner::test_oracle_runner_instantiation - ImportError: oracledb package is required
FAILED tests/test_database_sanity.py::TestMSSQLRunner::test_mssql_runner_instantiation - ImportError: pyodbc package is required
FAILED tests/test_database_sanity.py::TestPrestoRunner::test_presto_runner_instantiation - ImportError: pyhive package is required
FAILED tests/test_database_sanity.py::TestHiveRunner::test_hive_runner_instantiation - ImportError: pyhive package is required
FAILED tests/test_agent_memory_sanity.py::TestFAISSAgentMemory::test_faiss_instantiation - AttributeError: 'FAISSAgentMemory' object has no attribute 'persist_path'

After

SKIPPED tests/test_database_sanity.py::TestClickHouseRunner::test_clickhouse_runner_instantiation - clickhouse_connect not installed
SKIPPED tests/test_database_sanity.py::TestOracleRunner::test_oracle_runner_instantiation - oracledb not installed
SKIPPED tests/test_database_sanity.py::TestMSSQLRunner::test_mssql_runner_instantiation - pyodbc not installed
SKIPPED tests/test_database_sanity.py::TestPrestoRunner::test_presto_runner_instantiation - pyhive not installed
SKIPPED tests/test_database_sanity.py::TestHiveRunner::test_hive_runner_instantiation - pyhive not installed
PASSED tests/test_agent_memory_sanity.py::TestFAISSAgentMemory::test_faiss_instantiation

Test Results

Full local test suite (excluding integration tests requiring API keys):

210 passed, 5 skipped in 5.78s

Checklist

• ruff format — no changes needed
• ruff check — all checks passed
• All existing tests still pass
• Follows project conventions (commit message format, skip pattern)