feat: xAI image generate/edit, API key import, and per-provider timeouts

- Add dedicated xAI image adapter with generate + edit (multi-image) via
  /v1/images/generations and /v1/images/edits, plus aspect_ratio/resolution UI
- Support importing existing API keys and exposing connection api-key routes
- Add global/per-provider connect timeout overrides from settings
- Keep unrelated provider UX improvements on this branch; no Grok quota tracking

open-sse/executors/base.js

@@ -2,6 +2,7 @@ import { HTTP_STATUS, RETRY_CONFIG, DEFAULT_RETRY_CONFIG, resolveRetryEntry, FET
 import { shouldRefreshCredentials } from "../services/oauthCredentialManager.js";
 import { proxyAwareFetch } from "../utils/proxyFetch.js";
 import { dbg } from "../utils/debugLog.js";
+import { resolveProviderTimeoutMs } from "../services/providerTimeout.js";
 import { ANTHROPIC_API_VERSION, OPENAI_COMPAT_BASE, ANTHROPIC_COMPAT_BASE } from "../providers/shared.js";
 
 /**
@@ -132,7 +133,7 @@ export class BaseExecutor {
 
       // Abort if upstream doesn't return response headers within connection timeout
       const connectCtrl = new AbortController();
-      const timeoutMs = this.config?.timeoutMs || FETCH_CONNECT_TIMEOUT_MS;
+      const timeoutMs = await resolveProviderTimeoutMs(this.provider, this.config?.timeoutMs, FETCH_CONNECT_TIMEOUT_MS);
       const connectTimer = setTimeout(() => connectCtrl.abort(new Error("fetch connect timeout")), timeoutMs);
       const mergedSignal = signal ? AbortSignal.any([signal, connectCtrl.signal]) : connectCtrl.signal;