Feat: add env-driven LLM configuration and smoke test

server/_core/env.ts

@@ -1,3 +1,14 @@
+const parseInteger = (value: string | undefined, fallback: number) => {
+  if (!value) return fallback;
+  const parsed = Number.parseInt(value, 10);
+  return Number.isFinite(parsed) ? parsed : fallback;
+};
+
+const parseBoolean = (value: string | undefined, fallback: boolean) => {
+  if (value == null || value === "") return fallback;
+  return value === "1" || value.toLowerCase() === "true";
+};
+
 export const ENV = {
   appId: process.env.VITE_APP_ID ?? "",
   cookieSecret: process.env.JWT_SECRET ?? "",
@@ -7,4 +18,15 @@ export const ENV = {
   isProduction: process.env.NODE_ENV === "production",
   forgeApiUrl: process.env.BUILT_IN_FORGE_API_URL ?? "",
   forgeApiKey: process.env.BUILT_IN_FORGE_API_KEY ?? "",
+  llmApiUrl:
+    process.env.LLM_API_URL ??
+    (process.env.BUILT_IN_FORGE_API_URL
+      ? `${process.env.BUILT_IN_FORGE_API_URL.replace(/\/$/, "")}/v1/chat/completions`
+      : ""),
+  llmApiKey:
+    process.env.LLM_API_KEY ?? process.env.BUILT_IN_FORGE_API_KEY ?? "",
+  llmModel: process.env.LLM_MODEL ?? "gemini-2.5-flash",
+  llmMaxTokens: parseInteger(process.env.LLM_MAX_TOKENS, 32768),
+  llmEnableThinking: parseBoolean(process.env.LLM_ENABLE_THINKING, false),
+  llmThinkingBudget: parseInteger(process.env.LLM_THINKING_BUDGET, 128),
 };