fix(mcp): preserve FalkorDB URI username

[he-yufeng]

Summary

Fixes #1522.

FalkorDB Cloud URIs can include a username, for example redis://falkordb:<password>@host:port. The MCP server factory parsed host and port from FALKORDB_URI, but dropped parsed.username; GraphitiService then built FalkorDriver without a username, so the client authenticated as the implicit Redis default user.

This keeps the existing URI/password behavior and adds username propagation:

• parse the username from FALKORDB_URI
• allow FALKORDB_USERNAME / config username to override it
• pass the username into FalkorDriver
• add MCP server config tests for URI username preservation and env override

To verify

• $env:PYTHONPATH='..;src'; python -m pytest tests\test_falkordb_config.py -q -> 2 passed
• python -m py_compile src\config\schema.py src\services\factories.py src\graphiti_mcp_server.py tests\test_falkordb_config.py
• python -m ruff check src\config\schema.py src\services\factories.py src\graphiti_mcp_server.py tests\test_falkordb_config.py
• python -m ruff format --check src\config\schema.py src\services\factories.py src\graphiti_mcp_server.py tests\test_falkordb_config.py
• git diff --check

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[he-yufeng]

Rebased this branch onto the latest upstream main and force-pushed the cleaned head.

Validated locally:

• python -m py_compile mcp_server/src/config/schema.py mcp_server/src/graphiti_mcp_server.py mcp_server/src/services/factories.py mcp_server/tests/test_falkordb_config.py
• PYTHONPATH=<repo-root>;mcp_server/src uv run pytest -q mcp_server/tests/test_falkordb_config.py (2 passed)
• git diff --check origin/main..HEAD

The remaining GitHub failures appear to be repository automation credentials (CLAAssistant, review, triage) rather than a test failure from this patch.

[he-yufeng]

Rebased this branch onto current getzep:main and reran the focused validation.

Validation:

python -m py_compile mcp_server\src\config\schema.py mcp_server\src\graphiti_mcp_server.py mcp_server\src\services\factories.py mcp_server\tests\test_falkordb_config.py
PYTHONPATH=<repo-root>;mcp_server/src uv run pytest -q mcp_server\tests\test_falkordb_config.py
# 2 passed
git diff --check origin/main..HEAD

Remaining non-code item: the CLA Assistant still requires the contributor agreement comment from my account.

[he-yufeng]

Rebased this branch onto the current getzep:main and reran the focused validation.

Validation:

python -m py_compile mcp_server\src\config\schema.py mcp_server\src\graphiti_mcp_server.py mcp_server\src\services\factories.py mcp_server\tests\test_falkordb_config.py
PYTHONPATH=<repo-root>;mcp_server/src uv run --frozen pytest -q mcp_server\tests\test_falkordb_config.py
# 2 passed
git diff --check upstream/main..HEAD

Current head: 7f7099b.

I have read the CLA Document and I hereby sign the CLA on behalf of myself, e-mail: [email protected]

[he-yufeng]

I have read the CLA Document and I hereby sign the CLA behalf on myself, e-mail: [email protected]