fix(gitlawb): add specialty validators for connection test — bypass /models probe

GitLawB OpenGateway API (xiaomi-mimo compatible) does not expose a /models
endpoint, causing validateOpenAILikeProvider to 404 on the initial probe
and report 'Provider validation endpoint not supported'.

Add specialty validators for both gitlawb and gitlawb-gmi that follow the
same pattern as the existing xiaomi-mimo validator: skip GET /models,
validate directly via POST /chat/completions with a minimal test message.
Any 401/403 response means an invalid key; all other responses mean auth
is OK.

Fixes test-connection returning 404 for GitLawB providers.

src/lib/providers/validation.ts

@@ -3743,6 +3743,64 @@ export async function validateProviderApiKey({ provider, apiKey, providerSpecifi
         return toValidationErrorResult(error);
       }
     },
+    // Gitlawb Opengateway — Xiaomi MiMo compatible, same /models endpoint limitation.
+    // Bypass /models probe in favor of chat/completions, matching xiaomi-mimo's pattern.
+    gitlawb: async ({ apiKey, providerSpecificData }: any) => {
+      try {
+        const baseUrl = normalizeBaseUrl(
+          providerSpecificData?.baseUrl || "https://opengateway.gitlawb.com/v1/xiaomi-mimo"
+        );
+        const chatUrl = `${baseUrl.replace(/\/chat\/completions$/, "")}/chat/completions`;
+        const res = await validationWrite(
+          chatUrl,
+          {
+            method: "POST",
+            headers: buildBearerHeaders(apiKey, providerSpecificData),
+            body: JSON.stringify({
+              model: "mimo-v2.5-pro",
+              messages: [{ role: "user", content: "test" }],
+              max_tokens: 1,
+            }),
+          },
+          isLocal
+        );
+        if (res.status === 401 || res.status === 403) {
+          return { valid: false, error: "Invalid API key" };
+        }
+        // Any non-auth response (200, 400, 422, 429) means auth passed
+        return { valid: true, error: null };
+      } catch (error: any) {
+        return toValidationErrorResult(error);
+      }
+    },
+    "gitlawb-gmi": async ({ apiKey, providerSpecificData }: any) => {
+      try {
+        const baseUrl = normalizeBaseUrl(
+          providerSpecificData?.baseUrl || "https://opengateway.gitlawb.com/v1/gmi-cloud"
+        );
+        const chatUrl = `${baseUrl.replace(/\/chat\/completions$/, "")}/chat/completions`;
+        const res = await validationWrite(
+          chatUrl,
+          {
+            method: "POST",
+            headers: buildBearerHeaders(apiKey, providerSpecificData),
+            body: JSON.stringify({
+              model: "XiaomiMiMo/MiMo-V2.5-Pro",
+              messages: [{ role: "user", content: "test" }],
+              max_tokens: 1,
+            }),
+          },
+          isLocal
+        );
+        if (res.status === 401 || res.status === 403) {
+          return { valid: false, error: "Invalid API key" };
+        }
+        // Any non-auth response (200, 400, 422, 429) means auth passed
+        return { valid: true, error: null };
+      } catch (error: any) {
+        return toValidationErrorResult(error);
+      }
+    },
     // Search providers — use factored validator
     ...Object.fromEntries(
       Object.entries(SEARCH_VALIDATOR_CONFIGS).map(([id, configFn]) => [