docs(readme): update leaderboard with Weave Router v0.62 (#1)

Weave Router v0.62 retook #1 on the leaderboard with Acc-Cost Arena
76.09 (up from 74.61 on v0.27), accuracy 79.32%, cost/1K $0.61.
Sqwish Router moves to #2 at 75.27. New v0.62 row:

- Acc-Cost Arena: 74.61 → 76.09
- Accuracy: 78.43 → 79.32
- Cost/1K: $0.92 → $0.61
- Opt. Selection: 1.27 → 5.60
- Opt. Cost: 12.10 → 17.19
- Opt. Accuracy: 89.56 → 89.21
- Robustness: 79.05 → 79.76

Submission PR: #102

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: steventohme

README.md

@@ -34,8 +34,8 @@ For more details, please see our [website](https://routeworks.github.io/leaderbo
 
 | Rank | Router | Affiliation | Acc-Cost Arena | Accuracy | Cost/1K Queries | Optimal Selection | Optimal Cost | Optimal Accuracy | Latency | Robustness |
 |------|--------------------|-----------------------------|--------|----------|---------|-----------------|--------------|----------------|---------|------------|
-| 🥇 | [Sqwish Router]() |  | 75.27 | 76.40 | $0.18 | 7.41 | 25.10 | 90.47 | — | 100.00 |
-| 🥈 | [Weave Router](https://workweave.dev) [[Code]](https://github.com/workweave/router) | 🎓 Weave | 74.61 | 78.43 | $0.92 | 1.27 | 12.10 | 89.56 | — | 79.05 |
+| 🥇 | [Weave Router](https://workweave.dev) [[Code]](https://github.com/workweave/router) | 🎓 Weave | 76.09 | 79.32 | $0.61 | 5.60 | 17.19 | 89.21 | — | 79.76 |
+| 🥈 | [Sqwish Router]() |  | 75.27 | 76.40 | $0.18 | 7.41 | 25.10 | 90.47 | — | 100.00 |
 | 🥉 | [R2-Router](https://arxiv.org/abs/2602.02823/) | 🎓 UCF | 71.60 | 71.23 | $0.06 | 24.51 | 48.70 | 99.85 | — | 45.71 |
 | 4 | [Auto Router]() |  | 70.05 | 70.17 | $0.12 | 37.58 | 40.02 | 86.04 | — | 49.52 |
 | 5 | [vLLM‑SR](https://vllm-semantic-router.com/) [[Code]](https://github.com/vllm-project/semantic-router) [[HF]](https://huggingface.co/llm-semantic-router) | 🎓 vLLM SR Team | 67.23 | 66.53 | $0.06 | 84.66 | 90.71 | 89.24 | — | 90.95 |