Filter out any tool whose inputSchema has an invalid x-mcp-header
annotation, per the draft requirement that a client MUST exclude such tools
from tools/list (server/tools #x-mcp-header). Each excluded tool is
reported via logWarn (tool name + the validation reason). Valid tools pass
through unchanged and in order. Separated as a pure static helper so the
exclusion can be unit-tested without a live server; listTools calls it only
for a draft session (the feature is draft-only and HTTP-transport-specific).
Filter out any tool whose inputSchema has an invalid x-mcp-header annotation, per the draft requirement that a client MUST exclude such tools from tools/list (server/tools #x-mcp-header). Each excluded tool is reported via logWarn (tool name + the validation reason). Valid tools pass through unchanged and in order. Separated as a pure static helper so the exclusion can be unit-tested without a live server; listTools calls it only for a draft session (the feature is draft-only and HTTP-transport-specific).