test: add TestResources for 7 MCP resources (closes #7)

[ThomsenDrake]

Summary

Adds a TestResources class with 7 tests covering all zero-coverage MCP resources from issue #7:

Test	Resource	Type
test_resource_script_opcodes	bitcoin://protocol/script-opcodes	Static
test_resource_address_types	bitcoin://protocol/address-types	Static
test_resource_sighash_types	bitcoin://protocol/sighash-types	Static
test_resource_connection_status	bitcoin://connection/status	Dynamic
test_resource_node_status	bitcoin://node/status	Dynamic
test_resource_current_fees	bitcoin://fees/current	Dynamic
test_resource_mempool_snapshot	bitcoin://mempool/snapshot	Dynamic

Approach

• Static resources (opcodes, address types, sighash types): validate returned JSON structure and presence of known keys
• Dynamic resources (connection status, node status, fees, mempool): use the existing mock_rpc fixture which already mocks all required RPC calls

Test results

All 131 tests pass (124 existing + 7 new):

tests/test_server.py::TestResources::test_resource_script_opcodes PASSED
tests/test_server.py::TestResources::test_resource_address_types PASSED
tests/test_server.py::TestResources::test_resource_sighash_types PASSED
tests/test_server.py::TestResources::test_resource_connection_status PASSED
tests/test_server.py::TestResources::test_resource_node_status PASSED
tests/test_server.py::TestResources::test_resource_current_fees PASSED
tests/test_server.py::TestResources::test_resource_mempool_snapshot PASSED
``"

Closes #7

[Bortlesboat]

Closing this as superseded by #31, which consolidates the open backlog work into one maintainer sweep. Thank you for the contribution and the concrete issue coverage here.