feat(kbdb,mcp): KBDB 資料層薄殼 + self-hosted MCP 認證 + cypher KBDB proxy

三件一條鏈（HANDOFF §2/§3b，kbdb-base Phase 9）：

A. KBDB MCP 薄殼（9.1）：mcp/src/tools/kbdb_data.ts 6 工具
   template/record/query/search，調基本盤 API。鐵律：不給建表/SQL，只 template+slot。

B. MCP self-hosted 認證 401（mcp-account-source §5.5）：
   - partner-auth.ts：MULTI_TENANT=false 時 Bearer 明碼直接當 org_namespace，
     繞 KBDB partner 驗證（對齊 cypher 的 opaque-key 模型）。官方 SaaS 行為不變、共用同碼。
   - mcp-setup.ts：把 namespace/api_key 寫進 .mcp.json headers.Authorization。
   - 新增 self-hosted vs SaaS 分支單測（9 tests 綠）。

C. cypher KBDB proxy（9.5）+ CLI 薄殼（9.2）：
   - routes/kbdb-proxy.ts 純轉發 /kbdb/* → KBDB 基本盤（KBDB_BASE_URL HTTP fetch，
     不新增 service binding）。讓 CLI（只認證到 cypher）能達獨立 KBDB worker。
   - 租戶隔離：X-Arcrun-API-Key 自動當 owner_id 注入 records/entries（強制覆寫防跨租戶）；
     templates 全域共享（虛擬表定義是 schema 非資料）。
   - cli/src/commands/kbdb.ts：acr kbdb template/record/query/search，與 MCP kbdb_* 同能力。
   - kbdb base：entries 加 page_name 過濾（9.3）。

cypher + cli + mcp tsc exit 0。未驗收：端到端需 deploy + KBDB_BASE_URL 可達後實測。

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

kbdb/src/actions/entry-crud.ts

@@ -56,6 +56,7 @@ export interface ListEntriesFilter {
   entry_type?: string;
   owner_id?: string;
   parent_id?: string;
+  page_name?: string;   // exact-match lookup (e.g. skill-/example- idempotency key)
   limit?: number;
   offset?: number;
 }
@@ -66,6 +67,7 @@ export async function listEntries(db: D1Database, f: ListEntriesFilter = {}): Pr
   if (f.entry_type) { conds.push('entry_type = ?'); params.push(f.entry_type); }
   if (f.owner_id) { conds.push('owner_id = ?'); params.push(f.owner_id); }
   if (f.parent_id) { conds.push('parent_id = ?'); params.push(f.parent_id); }
+  if (f.page_name) { conds.push('page_name = ?'); params.push(f.page_name); }
   const where = conds.length ? `WHERE ${conds.join(' AND ')}` : '';
   const limit = Math.min(f.limit ?? 100, 1000);
   const offset = f.offset ?? 0;

kbdb/src/routes/entries.ts

@@ -20,13 +20,15 @@ entryRoutes.post('/', async (c) => {
   return c.json({ success: true, entry });
 });
 
-// GET /entries — list with filters (entry_type, owner_id, parent_id)
+// GET /entries — list with filters (entry_type, owner_id, parent_id, page_name)
 // e.g. list workflows under a project: ?parent_id=PROJECT&entry_type=workflow
+// e.g. get one by idempotency key: ?page_name=skill-rag_with_arcrun
 entryRoutes.get('/', async (c) => {
   const entries = await listEntries(c.env.DB, {
     entry_type: c.req.query('entry_type') || undefined,
     owner_id: c.req.query('owner_id') || undefined,
     parent_id: c.req.query('parent_id') || undefined,
+    page_name: c.req.query('page_name') || undefined,
     limit: c.req.query('limit') ? Number(c.req.query('limit')) : undefined,
     offset: c.req.query('offset') ? Number(c.req.query('offset')) : undefined,
   });