system-monitor: live pm2 log streaming — click a process name to tail its logs

- GET /api/system-monitor/pm2/logs?id=<pm_id>&lines=<n> — SSE that spawns
  `pm2 logs <id> --raw` (combined out+err, follows live) and streams each line.
  id validated numeric + passed as a spawn arg (no shell); killed on disconnect.
- Pm2View: clicking a process name drills into Pm2Logs (EventSource tail with a
  live pulse + back button); autoscrolls, capped at ~1200 lines.

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

src/servers/api/system-monitor/system-monitor.ts

@@ -199,3 +199,83 @@ systemMonitorRouter.get('/docker', async (ctx) => {
     return ctx.json({ containers: [], error: err instanceof Error ? err.message : String(err) });
   }
 });
+
+// GET /pm2/logs?id=<pm_id>&lines=<n> — SSE stream of a pm2 process's live logs (combined out+err via
+// `pm2 logs <id> --raw`). id is validated numeric and passed as a spawn arg (no shell) — no injection.
+systemMonitorRouter.get('/pm2/logs', (ctx) => {
+  const id = ctx.req.query('id') ?? '';
+  if (!/^\d+$/.test(id)) return ctx.text('numeric pm2 id required', 400);
+  const lines = Math.min(1000, Math.max(0, Number(ctx.req.query('lines')) || 100));
+
+  const enc = new TextEncoder();
+  const stream = new ReadableStream<Uint8Array>({
+    start(controller) {
+      let proc: ReturnType<typeof Bun.spawn> | null = null;
+      let closed = false;
+      const send = (line: string) => {
+        try {
+          controller.enqueue(enc.encode(`data: ${line}\n\n`));
+        } catch {
+          /* closed */
+        }
+      };
+      const cleanup = () => {
+        if (closed) return;
+        closed = true;
+        clearInterval(hb);
+        try {
+          proc?.kill();
+        } catch {
+          /* already gone */
+        }
+        try {
+          controller.close();
+        } catch {
+          /* already closed */
+        }
+      };
+
+      try {
+        proc = Bun.spawn(['pm2', 'logs', id, '--raw', '--lines', String(lines)], { stdout: 'pipe', stderr: 'pipe' });
+      } catch (err) {
+        send(`[error spawning pm2 logs: ${String(err)}]`);
+        controller.close();
+        return;
+      }
+
+      void (async () => {
+        const reader = (proc!.stdout as ReadableStream<Uint8Array>).getReader();
+        const dec = new TextDecoder();
+        let buf = '';
+        try {
+          while (true) {
+            const { done, value } = await reader.read();
+            if (done) break;
+            buf += dec.decode(value, { stream: true });
+            const parts = buf.split('\n');
+            buf = parts.pop() ?? '';
+            for (const l of parts) send(l);
+          }
+        } catch {
+          /* stream ended */
+        } finally {
+          cleanup();
+        }
+      })();
+
+      const hb = setInterval(() => {
+        try {
+          controller.enqueue(enc.encode(': hb\n\n'));
+        } catch {
+          /* closed */
+        }
+      }, 15_000);
+      ctx.req.raw.signal.addEventListener('abort', cleanup);
+      setTimeout(cleanup, 60 * 60 * 1000);
+    },
+  });
+
+  return new Response(stream, {
+    headers: { 'Content-Type': 'text/event-stream', 'Cache-Control': 'no-cache', Connection: 'keep-alive' },
+  });
+});