docs(kld): publish GLM-5.3 QAD fidelity comparison

Document the QAD step 1,750 checkpoint identity, exact-route and natural-route BF16 fidelity results, paired held-out decision criteria, routing behavior, training-data overlap audit, limitations, and receipt hashes. Link the research-only result from the KLD and GLM model hubs and generated index.\n\nCompatibility: documentation only; the qualified GLM serving target and runtime are unchanged.\n\nValidation: paired values checked against retained JSON receipts, Markdown table widths checked, relative links resolved, internal-path and direct-Discord scans passed, and git diff --check passed.