fix: string array sort with custom comparator

[cs01]

Summary

• ["c","a","b"].sort((a, b) => ...) was silently broken — comparator received raw pointer values as doubles instead of string args
• root cause: sort codegen always dispatched to numeric sort loop (loading doubles from %Array), and callback param type hint only filled first param
• added generateStringSortWithFn that uses %StringArray struct and passes i8* strings
• fixed orchestrator to fill callback param type hints for ALL arrow function params, not just the first

Test plan

• new fixture arrays/string-sort-comparator.ts — ascending and descending custom sort
• npm run verify:quick passes (self-hosting + all tests)
• works on both JS and native compiler