docs: move PR #45 link to top of weight compression paper

Co-Authored-By: tturney@psyguard.ai
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docs/papers/weight-compression-tq4.md

@@ -4,6 +4,9 @@
 Independent Researcher
 GitHub: [@TheTom](https://github.com/TheTom)
 
+**Code:** [PR #45](https://github.com/TheTom/llama-cpp-turboquant/pull/45) — branch `pr/tq4-weight-compression` (Metal only, CUDA port needed)
+**Getting started:** [docs/getting-started.md](https://github.com/TheTom/turboquant_plus/blob/main/docs/getting-started.md)
+
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 ## Acknowledgment