* fix(mcp): deliver tool errors within advertised schema contracts
Retain complete typed JSON error content while omitting non-conforming
structured errors at the public transport boundary. Recover oversized
diagnostics into Evidence before removing their private structured carrier.
Update schema-validated client readers and cover actual stdio delivery.
Closes#1261
Assisted-by: Kogasa (gensokyo-skills:kogasa-surprise-testing)
* test(mcp): read typed errors in canonical Evidence regressions
* test(mcp): validate public error diagnostics in acceptance workflows
Ysopwnable
7e96f25f8b