feat: robust GraphQL query builder, SOAP fixes, faster startup

[testsmith-io]

GraphQL:

• Build/insert queries via the AST (parse -> insert -> print) so an insert from the schema explorer is always valid syntax; required args become typed variables (with signature + variables JSON kept in sync), objects/unions get valid selection sets.
• Only add truly-required args: honor default values (first: Int! = 10 is optional), inline required pagination as a number, "all fields" action, "hide fields that require arguments" filter, and mark required args with !.
• Live schema validation status; fetch arg defaultValue in introspection.
• Fix schema-explorer vertical scrolling.

SOAP:

• Disambiguate same-named operations across 1.1/1.2 bindings (persist soapVersion + binding); fix the detail panel scrolling.

Other:

• Response table row numbers start at 1.
• Cmd/Ctrl+Enter (re)sends the active request.
• Faster startup: drop the fixed 1.2s splash delay (min-visible time instead) and lazy-load the GraphQL/SOAP editors (-448 kB from the initial chunk).