fix(tui): resolve wrong provider prefix when session has model without modelProvider (#25874)

Merged via /review-pr -> /prepare-pr -> /merge-pr.

Prepared head SHA: f0953a7284
Co-authored-by: lbo728 <72309817+lbo728@users.noreply.github.com>
Co-authored-by: gumadeiras <5599352+gumadeiras@users.noreply.github.com>
Reviewed-by: @gumadeiras

src/agents/model-selection.ts

@@ -171,6 +171,42 @@ export function parseModelRef(raw: string, defaultProvider: string): ModelRef |
   return normalizeModelRef(providerRaw, model);
 }
 
+export function inferUniqueProviderFromConfiguredModels(params: {
+  cfg: OpenClawConfig;
+  model: string;
+}): string | undefined {
+  const model = params.model.trim();
+  if (!model) {
+    return undefined;
+  }
+  const configuredModels = params.cfg.agents?.defaults?.models;
+  if (!configuredModels) {
+    return undefined;
+  }
+  const normalized = model.toLowerCase();
+  const providers = new Set<string>();
+  for (const key of Object.keys(configuredModels)) {
+    const ref = key.trim();
+    if (!ref || !ref.includes("/")) {
+      continue;
+    }
+    const parsed = parseModelRef(ref, DEFAULT_PROVIDER);
+    if (!parsed) {
+      continue;
+    }
+    if (parsed.model === model || parsed.model.toLowerCase() === normalized) {
+      providers.add(parsed.provider);
+      if (providers.size > 1) {
+        return undefined;
+      }
+    }
+  }
+  if (providers.size !== 1) {
+    return undefined;
+  }
+  return providers.values().next().value;
+}
+
 export function normalizeModelSelection(value: unknown): string | undefined {
   if (typeof value === "string") {
     const trimmed = value.trim();