fix: fire onSpawn immediately on job terminal transition (FAR-14)

Prevents process_lost false positives for 2-3 minute K8s jobs by
resetting the reaper clock when the keepalive loop detects the job
has completed (or been deleted), rather than waiting for the next
periodic refresh.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

src/server/execute.ts

@@ -883,6 +883,9 @@ export async function execute(ctx: AdapterExecutionContext): Promise<AdapterExec
           if (terminal) {
             keepaliveJobTerminal = true;
             keepaliveJobTerminalAt = Date.now();
+            if (ctx.onSpawn) {
+              void ctx.onSpawn({ pid: process.pid, processGroupId: null, startedAt: new Date().toISOString() }).catch(() => {});
+            }
             return;
           }
         } catch (err: unknown) {
@@ -893,6 +896,9 @@ export async function execute(ctx: AdapterExecutionContext): Promise<AdapterExec
           if (isK8s404(err)) {
             keepaliveJobTerminal = true;
             keepaliveJobTerminalAt = Date.now();
+            if (ctx.onSpawn) {
+              void ctx.onSpawn({ pid: process.pid, processGroupId: null, startedAt: new Date().toISOString() }).catch(() => {});
+            }
             return;
           }
           // Log transient errors but leave keepaliveJobTerminal false so