feat(systemd): unit overview + journal viewer pages

- Add journalctl_recent command and scrum4me-web to whitelist in commands.yml.example
- Add SYSTEMD_UNITS env var to .env.example
- lib/parse-systemd.ts: parse activeState, subState, uptime, description
- /app/systemd: server page reading SYSTEMD_UNITS, client list with 10s polling and status badges
- /app/systemd/[unit]: server detail page, client component showing systemctl status + last 100 journal lines (polling 10s)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/systemd/_components/systemd-units-list.tsx

@@ -0,0 +1,183 @@
+'use client'
+
+import { useCallback, useEffect, useState } from 'react'
+import Link from 'next/link'
+import { parseSystemctlStatus, type UnitStatus, type ActiveState } from '@/lib/parse-systemd'
+
+interface UnitEntry {
+  unit: string
+  status: UnitStatus | null
+  error: string | null
+}
+
+async function fetchUnitStatus(unit: string): Promise<UnitStatus> {
+  const res = await fetch('/api/agent/exec', {
+    method: 'POST',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify({ command_key: 'systemctl_status', args: [unit] }),
+  })
+
+  if (!res.ok) {
+    const text = await res.text()
+    throw new Error(`agent ${res.status}: ${text}`)
+  }
+
+  const reader = res.body?.getReader()
+  if (!reader) throw new Error('no response body')
+
+  const decoder = new TextDecoder()
+  let buffer = ''
+  let output = ''
+
+  while (true) {
+    const { done, value } = await reader.read()
+    if (done) break
+
+    buffer += decoder.decode(value, { stream: true })
+    const lines = buffer.split('\n')
+    buffer = lines.pop() ?? ''
+
+    for (const line of lines) {
+      if (line.startsWith('data:')) {
+        try {
+          const parsed = JSON.parse(line.slice(5).trim()) as { data?: string }
+          if (parsed.data !== undefined) output += parsed.data
+        } catch {
+          // ignore malformed
+        }
+      }
+    }
+  }
+
+  return parseSystemctlStatus(output, unit)
+}
+
+const badgeClass: Record<ActiveState, string> = {
+  active: 'bg-green-100 text-green-800 dark:bg-green-900/30 dark:text-green-400',
+  inactive: 'bg-zinc-100 text-zinc-600 dark:bg-zinc-800 dark:text-zinc-400',
+  failed: 'bg-red-100 text-red-800 dark:bg-red-900/30 dark:text-red-400',
+  activating: 'bg-amber-100 text-amber-800 dark:bg-amber-900/30 dark:text-amber-400',
+  deactivating: 'bg-amber-100 text-amber-800 dark:bg-amber-900/30 dark:text-amber-400',
+  unknown: 'bg-zinc-100 text-zinc-600 dark:bg-zinc-800 dark:text-zinc-400',
+}
+
+const dotClass: Record<ActiveState, string> = {
+  active: 'bg-green-500 dark:bg-green-400',
+  inactive: 'bg-zinc-400 dark:bg-zinc-500',
+  failed: 'bg-red-500 dark:bg-red-400',
+  activating: 'bg-amber-500 dark:bg-amber-400',
+  deactivating: 'bg-amber-500 dark:bg-amber-400',
+  unknown: 'bg-zinc-400 dark:bg-zinc-500',
+}
+
+function StatusBadge({ status }: { status: UnitStatus }) {
+  const label = status.subState
+    ? `${status.activeState} (${status.subState})`
+    : status.activeState
+  return (
+    <span
+      className={`inline-flex items-center gap-1.5 rounded-full px-2 py-0.5 text-xs font-medium ${badgeClass[status.activeState]}`}
+    >
+      <span className={`size-1.5 rounded-full ${dotClass[status.activeState]}`} />
+      {label}
+    </span>
+  )
+}
+
+type Props = {
+  initialUnits: UnitEntry[]
+}
+
+export default function SystemdUnitsList({ initialUnits }: Props) {
+  const [units, setUnits] = useState<UnitEntry[]>(initialUnits)
+  const [refreshing, setRefreshing] = useState(false)
+  const [lastUpdated, setLastUpdated] = useState<Date>(new Date())
+
+  const refresh = useCallback(async () => {
+    setRefreshing(true)
+    try {
+      const updated = await Promise.all(
+        initialUnits.map(async (entry) => {
+          try {
+            const status = await fetchUnitStatus(entry.unit)
+            return { ...entry, status, error: null }
+          } catch (err) {
+            return { ...entry, status: null, error: err instanceof Error ? err.message : 'failed' }
+          }
+        }),
+      )
+      setUnits(updated)
+      setLastUpdated(new Date())
+    } finally {
+      setRefreshing(false)
+    }
+  }, [initialUnits])
+
+  useEffect(() => {
+    const id = setInterval(refresh, 10000)
+    return () => clearInterval(id)
+  }, [refresh])
+
+  return (
+    <div className="space-y-4">
+      <div className="flex items-center justify-between">
+        <div className="flex items-center gap-2">
+          <span className="text-sm text-muted-foreground">
+            {units.length} unit{units.length !== 1 ? 's' : ''}
+          </span>
+          {refreshing && (
+            <span className="text-xs text-muted-foreground animate-pulse">refreshing…</span>
+          )}
+        </div>
+        <span className="text-xs text-muted-foreground">
+          updated {lastUpdated.toLocaleTimeString()}
+        </span>
+      </div>
+
+      <div className="overflow-x-auto rounded-lg border border-border">
+        <table className="w-full text-sm">
+          <thead>
+            <tr className="border-b border-border bg-muted/50">
+              <th className="px-4 py-3 text-left font-medium text-muted-foreground">Unit</th>
+              <th className="px-4 py-3 text-left font-medium text-muted-foreground">Description</th>
+              <th className="px-4 py-3 text-left font-medium text-muted-foreground">Status</th>
+              <th className="px-4 py-3 text-left font-medium text-muted-foreground">Uptime</th>
+            </tr>
+          </thead>
+          <tbody>
+            {units.map((entry) => (
+              <tr
+                key={entry.unit}
+                className="border-b border-border last:border-0 hover:bg-muted/30 transition-colors"
+              >
+                <td className="px-4 py-3 font-mono text-xs">
+                  <Link
+                    href={`/systemd/${encodeURIComponent(entry.unit)}`}
+                    className="font-medium text-foreground hover:underline"
+                  >
+                    {entry.unit}
+                  </Link>
+                </td>
+                <td className="px-4 py-3 text-xs text-muted-foreground">
+                  {entry.status?.description ?? '—'}
+                </td>
+                <td className="px-4 py-3">
+                  {entry.error ? (
+                    <span className="text-xs text-destructive">{entry.error}</span>
+                  ) : entry.status ? (
+                    <StatusBadge status={entry.status} />
+                  ) : (
+                    <span className="text-xs text-muted-foreground">—</span>
+                  )}
+                </td>
+                <td className="px-4 py-3 text-xs text-muted-foreground">
+                  {entry.status?.uptime || '—'}
+                </td>
+              </tr>
+            ))}
+          </tbody>
+        </table>
+      </div>
+    </div>
+  )
+}