refactor: `McpError` renamed to `MCPError` and flatten parameters #372

Job	Run time
checks / readme-snippets	11s
checks / pre-commit	36s
checks / test (3.10, lowest-direct, windows-latest)	3m 18s
checks / test (3.13, locked, windows-latest)	2m 17s
checks / test (3.10, locked, ubuntu-latest)	46s
checks / test (3.12, lowest-direct, ubuntu-latest)	51s
checks / test (3.14, lowest-direct, ubuntu-latest)	1m 10s
checks / test (3.11, lowest-direct, windows-latest)	2m 37s
checks / test (3.13, lowest-direct, windows-latest)	3m 24s
checks / test (3.14, locked, ubuntu-latest)	2m 19s
checks / test (3.11, locked, ubuntu-latest)	44s
checks / test (3.13, locked, ubuntu-latest)	41s
checks / test (3.12, locked, windows-latest)	3m 15s
checks / test (3.11, lowest-direct, ubuntu-latest)	44s
checks / test (3.10, locked, windows-latest)	2m 43s
checks / test (3.14, locked, windows-latest)	3m 6s
checks / test (3.13, lowest-direct, ubuntu-latest)	45s
checks / test (3.11, locked, windows-latest)	3m 19s
checks / test (3.12, lowest-direct, windows-latest)	3m 33s
checks / test (3.14, lowest-direct, windows-latest)	2m 22s
checks / test (3.12, locked, ubuntu-latest)	48s
checks / test (3.10, lowest-direct, ubuntu-latest)	46s
all-green	5s
	40m 20s

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