Add Opus 4.5 and clean-up naming & remove legacy models for anthropic (#1892)

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<!-- This is an auto-generated description by cubic. -->
---
## Summary by cubic
Adds support for Anthropic Claude Opus 4.5 and standardizes Sonnet
naming. Removes legacy 3.x Anthropic models and updates tests to use the
new names.

- **New Features**
  - Added "Claude Opus 4.5" with 32k max output and 200k context.

- **Migration**
- Names standardized to "Claude Sonnet 4" and "Claude Sonnet 4.5".
Update any model selections and tests.
- Removed Anthropic 3.x models: Claude 3.7 Sonnet, Claude 3.5 Sonnet,
Claude 3.5 Haiku, and their Bedrock variants.

<sup>Written for commit fb0aff0bf5e21e1b57bc8744ed9643b863b888d4.
Summary will update automatically on new commits.</sup>

<!-- End of auto-generated description by cubic. -->

e2e-tests/engine.spec.ts

@@ -25,7 +25,7 @@ testSkipIfWindows(
     await po.setUpDyadPro();
     // By default, it's using auto which points to Flash 2.5 and doesn't
     // use engine.
-    await po.selectModel({ provider: "Anthropic", model: "Claude 4 Sonnet" });
+    await po.selectModel({ provider: "Anthropic", model: "Claude Sonnet 4" });
     await po.sendPrompt("[dump] tc=turbo-edits");
 
     await po.snapshotServerDump("request");