feat(phase7): pattern search, health check, keyboard shortcuts

- KeyList: pattern input for Redis MATCH, local filter, Go button
- ConnectionStore: health check interval (5s ping), healthOk state
- StatusBar: health indicator (unstable = yellow pulse)
- RedisService: ping, isConnected methods
- Sidebar: Delete key (Del), deselect (Esc), refresh (F5)
- useKeyboard: expanded shortcut map

src/main/ipc-handlers.ts

@@ -207,4 +207,10 @@ export function registerIpcHandlers(): void {
   ipcMain.handle('redis:existsKey', async (_e, id: string, key: string) => {
     return redisService.existsKey(id, key)
   })
+  ipcMain.handle('redis:ping', async (_e, id: string) => {
+    return redisService.ping(id)
+  })
+  ipcMain.handle('redis:isConnected', (_e, id: string) => {
+    return redisService.isConnected(id)
+  })
 }