Release dvr v1.6.1

[mhadifilms]

Release

Prepare DVR v1.6.1 with the MCP Python SDK 2 migration already validated in the merged implementation PR.

Included fix

• Replace removed MCP 1.x server decorators with MCP 2 low-level callbacks.
• Return MCP 2 result envelopes and snake-case Python model attributes.
• Exercise tools, resource listing, and resource reads through a full stdio handshake.

Validation

• Full DVR test suite passed under MCP 2.
• Ruff and mypy passed.