fix(litellm): idempotent MCP server provisioning + self-heal on login (SB-56)

provisionMcpServer now GETs /v1/mcp/server first and skips the POST if the
sitebridge_<id> entry already exists. upsertCustomer calls it on every
existing-customer login (fire-and-forget) so pre-existing customers whose
row was created before this code path shipped — or whose LiteLLM entry was
deleted/rebuilt — get their /mcp/ routing restored on next login.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/auth/customers.ts

@@ -1,6 +1,6 @@
 import { query, queryOne } from "../db/pool.js";
 import { encrypt, decrypt } from "../utils/crypto.js";
-import { provisionLiteLLMKey } from "./litellm.js";
+import { provisionLiteLLMKey, provisionMcpServer } from "./litellm.js";
 
 export interface Customer {
   id: string;
@@ -67,6 +67,14 @@ export async function upsertCustomer(params: {
     );
     existing.last_login_at = new Date();
     existing.name = params.name;
+
+    // Self-heal: ensure LiteLLM MCP server entry exists for this customer.
+    // Idempotent in provisionMcpServer; swallow errors so a LiteLLM hiccup
+    // doesn't block login.
+    provisionMcpServer(existing.id).catch((err) => {
+      console.error(`[customers] provisionMcpServer self-heal failed for ${existing.id}:`, err);
+    });
+
     return { customer: existing, virtualKey: getVirtualKey(existing), isNew: false };
   }
 

src/auth/litellm.ts

@@ -25,8 +25,26 @@ function toServerAlias(customerId: string): string {
   return `sitebridge_${customerId.replace(/-/g, "_")}`;
 }
 
+async function getMcpServer(serverAlias: string): Promise<LiteLLMMCPServerResponse | null> {
+  const res = await fetch(`${config.litellmUrl}/v1/mcp/server`, {
+    headers: { Authorization: `Bearer ${config.litellmMasterKey}` },
+  });
+  if (!res.ok) throw new Error(`LiteLLM /v1/mcp/server GET failed ${res.status}`);
+  const data = (await res.json()) as unknown;
+  const list = (Array.isArray(data)
+    ? data
+    : ((data as { data?: unknown; servers?: unknown }).data ??
+       (data as { servers?: unknown }).servers ??
+       [])) as LiteLLMMCPServerResponse[];
+  return list.find((s) => s.server_name === serverAlias || s.alias === serverAlias) ?? null;
+}
+
 export async function provisionMcpServer(customerId: string): Promise<string> {
   const serverAlias = toServerAlias(customerId);
+
+  const existing = await getMcpServer(serverAlias);
+  if (existing) return serverAlias;
+
   const demuxUrl = `${config.agilitonAccountUrl}/mcp/demux/${customerId}/mcp`;
 
   const body = {