fix(mcp-self-hosted): KBDB binding 指向不存在的 service + kbdb worker 未部署

self-hosted MCP failed 根因（壓測 2026-06-10）：
1. mcp/wrangler.toml: KBDB service binding 綁 'inkstone-kbdb-api'（全 repo 僅此一處，
   不存在的舊名）→ 改成實際 worker 名 'arcrun-kbdb'（官方+self-hosted 共用）。
2. deploy.ts: self-hosted 部署清單漏了 kbdb worker（只有 cypher/registry/mcp）→
   D1 arcrun-kbdb 有建但 worker 本體沒部署 → KBDB binding 指向不存在 service →
   partnerAuthMiddleware 每個 MCP 認證請求都 throw。加 'kbdb' 進部署清單。
D1 id 注入已涵蓋（injectWranglerConfig 跑 tier2，kbdb 現在在 tier2）。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

mcp/wrangler.toml

@@ -11,7 +11,7 @@ workers_dev = true   # 對齊 arcrun 部署慣例（rule 05）：deploy 掃描
 services = [
   { binding = "COMPONENT_REGISTRY", service = "arcrun-registry" },
   { binding = "CYPHER_EXECUTOR", service = "arcrun-cypher-executor" },
-  { binding = "KBDB", service = "inkstone-kbdb-api" }
+  { binding = "KBDB", service = "arcrun-kbdb" }
 ]
 
 # Route — MCP 搬進 arcrun 主庫後改用 arcrun.dev zone（與其他 worker 一致）。