Move the final inline emitInst handler groups (terminators, box/unbox-Any,
reflection, switch-branch, closure-creation, vector, block-param, misc) into
the Ops facade in src/backend/llvm/ops.zig. emitInst is now pure dispatch:
every arm delegates to self.ops().*, leaving only setInstDebugLocation plus
one-line delegations.
Widen the shared infra the moved bodies reach (emitFailableMainRet, getBlock,
anyTag, isSignedTypeEx, coerceToI64/coerceToI64Signed/coerceFromI64,
emitFieldValueGet) to pub on LLVMEmitter; helper and ref-tracking sections
stay put. Pure relocation: emitted LLVM IR byte-identical, zero snapshot churn.