feat(proxy): add universal proxy support and fix Gemini model resolution (#536)

Integrated undici ProxyAgent for native fetch and HttpsProxyAgent for axios/openai/anthropic. Upgraded @google/generative-ai to fix #536. Added OCO_PROXY config.

Co-authored-by: uni <uni@hanwei.ink>

package.json

@@ -89,7 +89,7 @@
     "@azure/openai": "^1.0.0-beta.12",
     "@clack/prompts": "^0.6.1",
     "@dqbd/tiktoken": "^1.0.2",
-    "@google/generative-ai": "^0.11.4",
+    "@google/generative-ai": "^0.24.1",
     "@mistralai/mistralai": "^1.3.5",
     "@octokit/webhooks-schemas": "^6.11.0",
     "@octokit/webhooks-types": "^6.11.0",
@@ -98,6 +98,7 @@
     "cleye": "^1.3.2",
     "crypto": "^1.0.1",
     "execa": "^7.0.0",
+    "https-proxy-agent": "^8.0.0",
     "ignore": "^5.2.4",
     "ini": "^3.0.1",
     "inquirer": "^9.1.4",