chore: import Local-Cursor v1.1.8 source snapshot

Includes the current working directory changes. Historical commits and release binaries are excluded to limit Gitea storage.
Source base: d7515973fbfd6dd2001fa156c483455b8081c7cb

internal/backend/agent/model/user_agent.go

@@ -0,0 +1,8 @@
+package modeladapter
+
+const (
+	// ClaudeCodeUserAgent 用于将渠道模型请求伪装为 Claude Code 客户端。
+	ClaudeCodeUserAgent = "claude-cli/2.1.19 (external, sdk-cli)"
+	// AnthropicClaudeCodeUserAgent 用于 Anthropic provider 的 Claude Code UA 兼容。
+	AnthropicClaudeCodeUserAgent = "claude-cli/1.0.25"
+)