feat: 添加 Bedrock API 客户端及 API 层增强

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/services/api/bedrockClient.ts

@@ -0,0 +1,65 @@
+import { AnthropicBedrock } from '@anthropic-ai/bedrock-sdk'
+
+/**
+ * Extends AnthropicBedrock to work around an upstream bug where the SDK
+ * re-plants the `anthropic-beta` HTTP header value into the request body
+ * as `anthropic_beta`. Bedrock's Opus 4.7 endpoint rejects any request with
+ * `anthropic_beta` in the body with a 400 "invalid beta flag" error.
+ *
+ * Source of the bug (SDK 0.26.4, still present through 0.28.1):
+ *   node_modules/@anthropic-ai/bedrock-sdk/client.js lines 122-127
+ *   (TS source: packages/bedrock-sdk/src/client.ts lines 193-198)
+ *
+ * Related upstream issue: anthropics/claude-code#49238 (opened 2026-04-16).
+ *
+ * Fix strategy: let super.buildRequest do its work, then strip
+ * `body.anthropic_beta` from the resulting Request before the SDK computes
+ * the AWS SigV4 signature (signing happens downstream of buildRequest, so
+ * the signature hashes the cleaned body — no 403 risk). The `anthropic-beta`
+ * HTTP header remains intact (base SDK placed it there from the `betas:`
+ * parameter), so beta flags still reach the API the way Bedrock accepts them.
+ *
+ * When upstream ships a fix, verify the probe in scripts/probe-bedrock-beta-fix.ts
+ * shows "bug reproduced: false", then delete this class and change
+ * `services/api/client.ts` to instantiate `AnthropicBedrock` directly.
+ */
+type BuildRequestArg = Parameters<AnthropicBedrock['buildRequest']>[0]
+type BuildRequestRet = Awaited<ReturnType<AnthropicBedrock['buildRequest']>>
+
+export class BedrockClient extends AnthropicBedrock {
+  async buildRequest(options: BuildRequestArg): Promise<BuildRequestRet> {
+    const req = await super.buildRequest(options)
+
+    const inner = (
+      req as unknown as { req?: { body?: unknown; headers?: unknown } }
+    )?.req
+    if (!inner || typeof inner.body !== 'string' || inner.body.length === 0) {
+      return req
+    }
+
+    let parsed: Record<string, unknown>
+    try {
+      parsed = JSON.parse(inner.body) as Record<string, unknown>
+    } catch {
+      return req
+    }
+    if (!('anthropic_beta' in parsed)) {
+      return req
+    }
+
+    delete parsed.anthropic_beta
+    const cleanedBody = JSON.stringify(parsed)
+    inner.body = cleanedBody
+
+    const byteLen = String(new TextEncoder().encode(cleanedBody).length)
+    const h = inner.headers
+    if (typeof Headers !== 'undefined' && h instanceof Headers) {
+      if (h.has('content-length')) h.set('content-length', byteLen)
+    } else if (h && typeof h === 'object') {
+      const asDict = h as Record<string, string>
+      if ('content-length' in asDict) asDict['content-length'] = byteLen
+    }
+
+    return req
+  }
+}