refactor: `McpError` renamed to `MCPError` and flatten parameters #377

Job	Run time
checks / pre-commit	31s
checks / readme-snippets	11s
checks / test (3.10, locked, ubuntu-latest)	48s
checks / test (3.11, lowest-direct, windows-latest)	3m 11s
checks / test (3.11, lowest-direct, ubuntu-latest)	54s
checks / test (3.11, locked, ubuntu-latest)	50s
checks / test (3.12, locked, windows-latest)	3m 23s
checks / test (3.11, locked, windows-latest)	2m 31s
checks / test (3.14, locked, windows-latest)	3m 11s
checks / test (3.13, lowest-direct, windows-latest)	2m 52s
checks / test (3.12, locked, ubuntu-latest)	52s
checks / test (3.12, lowest-direct, ubuntu-latest)	1m 0s
checks / test (3.13, locked, ubuntu-latest)	47s
checks / test (3.14, lowest-direct, windows-latest)	2m 39s
checks / test (3.10, lowest-direct, ubuntu-latest)	53s
checks / test (3.10, locked, windows-latest)	2m 17s
checks / test (3.13, lowest-direct, ubuntu-latest)	51s
checks / test (3.14, locked, ubuntu-latest)	2m 27s
checks / test (3.10, lowest-direct, windows-latest)	2m 28s
checks / test (3.12, lowest-direct, windows-latest)	3m 35s
checks / test (3.14, lowest-direct, ubuntu-latest)	1m 19s
checks / test (3.13, locked, windows-latest)	2m 22s
all-green	3s
	39m 55s

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