fix(anthropic): pass baseURL to client and handle thinking model responses

[ZITong926]

Summary

• Pass baseURL from config to the Anthropic SDK client. Without this, requests always go to https://api.anthropic.com even when OCO_API_URL is configured, resulting in 403 errors for users with custom API endpoints (e.g. corporate proxies).

• Find the text content block instead of accessing content[0].text. Models with extended thinking (e.g. Claude with thinking enabled, or thinking-capable models behind proxies) return a thinking block at index 0 and the actual text at index 1. The old code gets undefined from content[0].text since the thinking block has no text property, producing empty commit messages.

Reproduction

1. Set OCO_AI_PROVIDER=anthropic with a custom OCO_API_URL pointing to a proxy
2. Run oco → gets 403 Forbidden (Bug 1)
3. After manually fixing baseURL, run oco with a thinking model → gets empty commit message (Bug 2)

Fix

// Bug 1: pass baseURL
 const clientOptions: any = { apiKey: this.config.apiKey };
+if (this.config.baseURL) {
+  clientOptions.baseURL = this.config.baseURL;
+}

// Bug 2: find text block instead of content[0]
-const message = data?.content[0].text;
+const textBlock = data?.content?.find((b) => b.type === 'text');
+const message = textBlock && 'text' in textBlock ? textBlock.text : undefined;

Test plan

• Verified with custom OCO_API_URL — no more 403
• Verified with thinking model (GLM-5.1 via proxy) — commit message correctly extracted from text block
• Non-thinking models still work (fallback: first text block is at index 0 as before)

🤖 Generated with Claude Code

[di-sukharev]

Both fixes are correct in principle: the Anthropic client should receive baseURL, and the response should be searched for a text block. However, the resulting merge currently fails the required Prettier check. Please format it and add two regression cases to the existing anthropic.test: forwarding a custom baseURL, and a response containing a thinking block before the text block.

[di-sukharev]

The requested fixes are now complete. The custom base URL is forwarded to the Anthropic client, text extraction handles a leading thinking block, and both regressions are covered by focused tests. I also verified the combined merge with the other ready PRs: lint, typecheck, Prettier, build, 158 unit tests, and 34 end-to-end tests all pass. Approved.