feat(M3): SSH productization — Terminal/SSH split + Wave-style server monitoring

- Sidebar split into 本地终端 / SSH 服务器 sections + recent sessions quick reconnect
- SSH tabs carry server badge (icon + green edge); local tabs unchanged
- SSH session panels mount a collapsible live monitor panel (CPU/mem/disk/net/load/uptime)
- src/main/sysinfo.ts polls remote via ssh2 exec (/proc + df), 3s interval,
  error-tolerant (3 consecutive failures auto-stop), auto-stops on session close
- tests: sysinfo-e2e (loopback exec with canned /proc output) — ALL PASSED

src/main/pty.ts

@@ -6,6 +6,11 @@ import type { SessionOpenOptions, HostKeyPromptEvent, SshConnection } from '../s
 import { broadcast } from './broadcast'
 import { connectSsh, type SshSessionHandle } from './ssh'
 import type { HostKeyCheckResult } from './knownHosts'
+import { configureSysinfo, registerSysinfoClient, stopPolling } from './sysinfo'
+
+// Re-export so the session-layer loopback bundle (tests/*-e2e.mjs) can drive the
+// M3 polling engine without importing src/main/sysinfo.ts separately.
+export { startPolling, stopPolling } from './sysinfo'
 
 /**
  * Session routing table. A session is either a local pty or an established ssh
@@ -64,6 +69,14 @@ let runtimeDeps: SessionRuntimeDeps | undefined
 /** Wire the real stores + renderer prompt. Called once during app startup. */
 export function configureSessionRuntime(deps: SessionRuntimeDeps): void {
   runtimeDeps = deps
+  configureSysinfo({
+    broadcast: (channel, ...args) => deps.broadcast(channel, ...args)
+  })
+  registerSysinfoClient((id) => {
+    const session = sessions.get(id)
+    if (session?.kind === 'ssh') return session.ssh.client
+    return undefined
+  })
 }
 
 function defaultShell(): string {
@@ -156,6 +169,7 @@ export async function openSession(opts: SessionOpenOptions): Promise<{ id: strin
 
   handle.stream.on('close', () => {
     try {
+      stopPolling(handle.id)
       sessions.delete(handle.id)
       deps.broadcast(Ipc.PTY_EXIT, { id: handle.id, exitCode: 0 })
     } catch {
@@ -190,6 +204,7 @@ export function resizePty(id: string, cols: number, rows: number): void {
 }
 
 export function killPty(id: string): void {
+  stopPolling(id)
   replayBuffers.delete(id)
   const session = sessions.get(id)
   if (!session) return
@@ -215,7 +230,10 @@ export function killPty(id: string): void {
 }
 
 export function killAllPtys(): void {
-  for (const session of sessions.values()) {
+  for (const id of sessions.keys()) {
+    stopPolling(id)
+    const session = sessions.get(id)
+    if (!session) continue
     if (session.kind === 'ssh') {
       try {
         session.ssh.stream.close()