feat(cypher-executor): implicit telemetry (LI SDD M1.2)

對應 .agents/specs/llm-interface/ Milestone 1.2。

新增 lib/telemetry.ts：
- hashApiKey(): SHA-256 截 16 hex 字元（不可逆，可聚合）
- recordTelemetry(): fetch fire-and-forget 寫 KBDB type=agent-telemetry block
- 設計：不阻擋主流程，錯誤 console.warn 不 throw
- 用 ctx.waitUntil 確保即使主 request 已回，背景仍會跑完

寫入點 3 處：
1. routes/webhooks-named.ts POST /webhooks/named (deploy) → deploy_success
2. routes/webhooks-named.ts POST /webhooks/named/:name/trigger →
   executeWebhookGraph 帶 ctx + userAgent，內部記 run_success / run_fail
3. routes/validate.ts POST /validate → validation_error (含 schema_failed / edge_node_missing)

executeWebhookGraph 簽名擴張：可選 ctx + userAgent，舊 caller (scheduled /
trigger_workflow / anonymous webhook) 不傳也 OK（telemetry 仍寫但無 ctx 加持）。

paused (workflow 因 claude_api 等等 callback resume) 算 run_success，
不污染 fail metric。

types.ts: 加 PLATFORM_API_KEY env (可選) + re-export ExecutionContext

不違反「業務邏輯走 WASM」鐵律：telemetry 是 orchestrator 觀測自身的能力，
跟 trigger_workflow / scheduled() 同類。

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

cypher-executor/src/actions/webhook-handlers.ts

@@ -1,8 +1,9 @@
-import type { Bindings, ExecutionGraph } from '../types';
+import type { Bindings, ExecutionGraph, ExecutionContext } from '../types';
 import { ExecutionError } from '../types';
 import { GraphExecutor } from '../graph-executor';
 import { graphSchema } from '../lib/schemas';
 import { createComponentLoader } from '../lib/component-loader';
+import { recordTelemetry } from '../lib/telemetry';
 
 type WebhookRecord = {
   graph: Record<string, unknown>;
@@ -29,6 +30,8 @@ export async function executeWebhookGraph(
   triggerContext: Record<string, unknown>,
   token: string,
   apiKey?: string,
+  ctx?: ExecutionContext,        // 可選 — 用 waitUntil 把 telemetry 推到背景
+  userAgent?: string,            // MCP / SDK client 帶過來
 ): Promise<{ success: boolean; data?: unknown; error?: string; trace?: unknown; duration_ms: number }> {
   const parsed = graphSchema.safeParse(graph);
   if (!parsed.success) {
@@ -46,10 +49,30 @@ export async function executeWebhookGraph(
       env.EXEC_CONTEXT,
     );
     const duration_ms = Date.now() - start;
+
+    // Implicit telemetry：成功 run（含 paused 也算「成功啟動」由 trigger_workflow 那層分類）
+    recordTelemetry(env, apiKey, {
+      event_type: 'run_success',
+      workflow_name: token,
+      duration_ms,
+      agent_user_agent: userAgent,
+    }, ctx);
+
     return { success: true, data: result.data, duration_ms };
   } catch (err) {
     const duration_ms = Date.now() - start;
     const errMsg = err instanceof Error ? err.message : String(err);
+    const isPaused = /workflow paused/i.test(errMsg);
+
+    // Implicit telemetry：paused 算 run_success；真錯才 run_fail
+    recordTelemetry(env, apiKey, {
+      event_type: isPaused ? 'run_success' : 'run_fail',
+      workflow_name: token,
+      error_code: isPaused ? 'paused_awaiting_resume' : 'execution_error',
+      duration_ms,
+      agent_user_agent: userAgent,
+    }, ctx);
+
     if (err instanceof ExecutionError) {
       const traceFormatted = err.trace.map(s => ({
         node: s.nodeId,