feat(server): instance-centric controls — real per-instance state + lifecycle

The Server page now manages the selected GAME INSTANCE, not the legacy
host connection. New instances store flattens the fleet and drives the
command bridge. New 'Game instance' panel: real state badge
(running/stopped/crashed/configured), uptime, host, and an instance
selector when >1. Start/Stop/Restart/Refresh wired to POST
/api/instances/:id/lifecycle — gated on the actual instance state (not
host connectivity), with telemetry-only instances flagged. Works across
all four games (state + lifecycle are game-agnostic).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend/src/stores/instances.ts

@@ -0,0 +1,106 @@
+import { defineStore } from 'pinia'
+import { ref, computed } from 'vue'
+import { useApi } from '@/composables/useApi'
+import type { FleetData, FleetInstance } from '@/stores/fleet'
+
+/** A game instance enriched with its host context, flattened from the fleet. */
+export interface ManagedInstance extends FleetInstance {
+  host_id: string
+  host_hostname: string
+  host_status: string
+}
+
+type LifecycleAction = 'start' | 'stop' | 'restart' | 'status' | 'steam_update'
+
+/**
+ * Instance management — the Server page operates on a selected game instance
+ * (not the legacy single-server connection). Reads the fleet to enumerate
+ * instances and drives the per-instance command bridge
+ * (POST /api/instances/:id/lifecycle | /rcon).
+ */
+export const useInstancesStore = defineStore('instances', () => {
+  const instances = ref<ManagedInstance[]>([])
+  const currentId = ref<string | null>(null)
+  const loading = ref(false)
+  const acting = ref<LifecycleAction | null>(null)
+  const error = ref<string | null>(null)
+
+  const api = useApi()
+
+  const current = computed<ManagedInstance | null>(
+    () => instances.value.find((i) => i.id === currentId.value) ?? null,
+  )
+
+  /** Fetch the fleet and flatten its instances. Optionally prefer a game. */
+  async function fetchInstances(preferGame?: string): Promise<void> {
+    loading.value = true
+    error.value = null
+    try {
+      const data = await api.get<FleetData>('/fleet')
+      const flat: ManagedInstance[] = []
+      for (const host of data.hosts) {
+        for (const inst of host.instances) {
+          flat.push({
+            ...inst,
+            host_id: host.id,
+            host_hostname: host.hostname,
+            host_status: host.status,
+          })
+        }
+      }
+      instances.value = flat
+      // Keep the current selection if it still exists; else prefer the active
+      // game, else the first instance.
+      if (!flat.some((i) => i.id === currentId.value)) {
+        const preferred = preferGame ? flat.find((i) => i.game === preferGame) : undefined
+        currentId.value = (preferred ?? flat[0])?.id ?? null
+      }
+    } catch (e) {
+      console.error('Failed to fetch instances:', e)
+      error.value = e instanceof Error ? e.message : 'Failed to load instances'
+    } finally {
+      loading.value = false
+    }
+  }
+
+  function select(id: string): void {
+    currentId.value = id
+  }
+
+  /**
+   * Send a lifecycle command to the current instance. Returns the agent's
+   * reply (which carries the new state); refetches so the list reflects it.
+   * Throws on failure so the view can toast.
+   */
+  async function lifecycle(action: LifecycleAction): Promise<Record<string, unknown>> {
+    const id = currentId.value
+    if (!id) throw new Error('No instance selected')
+    acting.value = action
+    try {
+      const res = await api.post<Record<string, unknown>>(`/instances/${id}/lifecycle`, { action })
+      await fetchInstances()
+      return res
+    } finally {
+      acting.value = null
+    }
+  }
+
+  async function rcon(command: string): Promise<Record<string, unknown>> {
+    const id = currentId.value
+    if (!id) throw new Error('No instance selected')
+    return api.post<Record<string, unknown>>(`/instances/${id}/rcon`, { command })
+  }
+
+  return {
+    instances,
+    currentId,
+    current,
+    loading,
+    acting,
+    error,
+    fetchInstances,
+    select,
+    lifecycle,
+    rcon,
+  }
+})

frontend/src/views/admin/ServerView.vue

@@ -1,6 +1,7 @@
 <script setup lang="ts">
 import { ref, computed, onMounted } from 'vue'
 import { useServerStore } from '@/stores/server'
+import { useInstancesStore } from '@/stores/instances'
 import { useToastStore } from '@/stores/toast'
 import { useThemeGame } from '@/composables/useThemeGame'
 import { useGameProfile } from '@/config/gameProfiles'
@@ -19,9 +20,38 @@ import Switch from '@/components/ds/forms/Switch.vue'
 import Tabs from '@/components/ds/navigation/Tabs.vue'
 
 const server = useServerStore()
+const instancesStore = useInstancesStore()
 const toast = useToastStore()
 const { activeGame } = useThemeGame()
 
+// ---- Current game instance (the thing this page actually manages) ----
+const currentInstance = computed(() => instancesStore.current)
+const instanceState = computed(() => currentInstance.value?.state ?? null)
+const instanceRunning = computed(() => instanceState.value === 'running')
+const instanceManaged = computed(() =>
+  !!instanceState.value && !['unmanaged', 'configured', 'missing_root'].includes(instanceState.value),
+)
+const instanceStateTone = computed<'online' | 'offline' | 'warn'>(() => {
+  const s = instanceState.value
+  if (s === 'running') return 'online'
+  if (s === 'crashed') return 'warn'
+  return 'offline'
+})
+const instanceStateLabel = computed(() => {
+  const s = instanceState.value
+  if (!s) return 'No instance'
+  return s.charAt(0).toUpperCase() + s.slice(1).replace('_', ' ')
+})
+function fmtUptime(secs: number | undefined): string {
+  if (!secs || secs <= 0) return '—'
+  const d = Math.floor(secs / 86400)
+  const h = Math.floor((secs % 86400) / 3600)
+  const m = Math.floor((secs % 3600) / 60)
+  if (d > 0) return `${d}d ${h}h`
+  if (h > 0) return `${h}h ${m}m`
+  return `${m}m`
+}
+
 // Profile follows the GameSwitcher. 'all' defaults to rust (neutral house skin).
 const profile = computed(() => {
   const game = activeGame.value === 'all' ? 'rust' : activeGame.value
@@ -296,15 +326,32 @@ async function saveConfig() {
 }
 
 async function serverAction(action: 'start' | 'stop' | 'restart') {
+  if (!currentInstance.value) {
+    toast.error('No game instance to control — connect the host agent first')
+    return
+  }
   actionLoading.value = action
   try {
-    if (action === 'start') await server.startServer()
-    else if (action === 'stop') await server.stopServer()
-    else await server.restartServer()
-    await server.fetchServer()
-    toast.success(`Server ${action} command sent`)
+    const res = await instancesStore.lifecycle(action)
+    if ((res as { status?: string }).status === 'error') {
+      toast.error(String((res as { message?: string }).message ?? `Failed to ${action}`))
+    } else {
+      toast.success(`${currentInstance.value?.agent_instance_id ?? 'Instance'}: ${action} ok`)
+    }
+  } catch (e) {
+    toast.error(e instanceof Error ? e.message : `Failed to ${action} server`)
+  } finally {
+    actionLoading.value = null
+  }
+}
+
+async function refreshInstanceStatus() {
+  if (!currentInstance.value) return
+  actionLoading.value = 'status'
+  try {
+    await instancesStore.lifecycle('status')
   } catch {
-    toast.error(`Failed to ${action} server`)
+    /* status best-effort */
   } finally {
     actionLoading.value = null
   }
@@ -354,6 +401,9 @@ const connStatusTone = computed<'online' | 'offline' | 'warn'>(() => {
 onMounted(async () => {
   await server.fetchServer()
   loadFormFromConfig()
+  // Load the fleet's instances; prefer one matching the active game.
+  const game = activeGame.value === 'all' ? undefined : activeGame.value
+  await instancesStore.fetchInstances(game)
 
   // Fetch agent credentials for the TOML config block (leave null on error — honest fallback)
   try {
@@ -426,31 +476,93 @@ onMounted(async () => {
       </div>
     </Panel>
 
-    <!-- Controls -->
-    <Panel title="Controls">
-      <div class="sv__controls">
-        <Button
-          variant="outline"
-          icon="play"
-          :loading="actionLoading === 'start'"
-          :disabled="server.connection?.connection_status === 'connected' || actionLoading !== null"
-          @click="serverAction('start')"
-        >Start server</Button>
-        <Button
-          variant="danger-soft"
-          icon="power"
-          :loading="actionLoading === 'stop'"
-          :disabled="server.connection?.connection_status !== 'connected' || actionLoading !== null"
-          @click="serverAction('stop')"
-        >Stop server</Button>
-        <Button
-          variant="secondary"
-          icon="refresh-cw"
-          :loading="actionLoading === 'restart'"
-          :disabled="server.connection?.connection_status !== 'connected' || actionLoading !== null"
-          @click="serverAction('restart')"
-        >Restart server</Button>
-      </div>
+    <!-- Game instance — real per-instance state + lifecycle -->
+    <Panel title="Game instance">
+      <template #actions>
+        <Badge :tone="instanceStateTone" :dot="true" :pulse="instanceRunning">{{ instanceStateLabel }}</Badge>
+      </template>
+
+      <!-- No instance yet -->
+      <EmptyState
+        v-if="!currentInstance"
+        icon="server"
+        title="No game instance connected"
+        :description="'Install the host agent and add a ' + profile.label + ' instance to its config to manage it here.'"
+      />
+
+      <template v-else>
+        <!-- Instance selector when more than one -->
+        <div v-if="instancesStore.instances.length > 1" class="sv__instance-pick sv__mb">
+          <span class="sv__field-label">Instance</span>
+          <select
+            class="sv__select"
+            :value="instancesStore.currentId ?? ''"
+            @change="instancesStore.select(($event.target as HTMLSelectElement).value)"
+          >
+            <option v-for="i in instancesStore.instances" :key="i.id" :value="i.id">
+              {{ i.label || i.agent_instance_id }} ({{ i.game }}) · {{ i.host_hostname }}
+            </option>
+          </select>
+        </div>
+
+        <!-- Instance facts -->
+        <div class="sv__grid4 sv__mb">
+          <div class="sv__field">
+            <div class="sv__field-label">Instance</div>
+            <div class="sv__field-val sv__field-val--mono">{{ currentInstance.agent_instance_id }}</div>
+          </div>
+          <div class="sv__field">
+            <div class="sv__field-label">State</div>
+            <div class="sv__field-val sv__field-val--inline">
+              <StatusDot :tone="instanceStateTone" :pulse="instanceRunning" />
+              <span>{{ instanceStateLabel }}</span>
+            </div>
+          </div>
+          <div class="sv__field">
+            <div class="sv__field-label">Uptime</div>
+            <div class="sv__field-val sv__field-val--mono">{{ fmtUptime(currentInstance.uptime_seconds) }}</div>
+          </div>
+          <div class="sv__field">
+            <div class="sv__field-label">Host</div>
+            <div class="sv__field-val sv__field-val--mono">{{ currentInstance.host_hostname }}</div>
+          </div>
+        </div>
+
+        <!-- Lifecycle controls — gated on real instance state -->
+        <div class="sv__controls">
+          <Button
+            variant="outline"
+            icon="play"
+            :loading="actionLoading === 'start'"
+            :disabled="instanceRunning || !instanceManaged || actionLoading !== null"
+            @click="serverAction('start')"
+          >Start</Button>
+          <Button
+            variant="danger-soft"
+            icon="power"
+            :loading="actionLoading === 'stop'"
+            :disabled="!instanceRunning || actionLoading !== null"
+            @click="serverAction('stop')"
+          >Stop</Button>
+          <Button
+            variant="secondary"
+            icon="refresh-cw"
+            :loading="actionLoading === 'restart'"
+            :disabled="!instanceManaged || actionLoading !== null"
+            @click="serverAction('restart')"
+          >Restart</Button>
+          <Button
+            variant="ghost"
+            icon="refresh-cw"
+            :loading="actionLoading === 'status'"
+            :disabled="actionLoading !== null"
+            @click="refreshInstanceStatus"
+          >Refresh</Button>
+        </div>
+        <Alert v-if="!instanceManaged" tone="info" class="sv__mt-sm">
+          This instance is telemetry-only — add an <code>executable</code> to its agent config to enable start/stop.
+        </Alert>
+      </template>
     </Panel>
 
     <!-- Host agent -->
@@ -1013,6 +1125,19 @@ onMounted(async () => {
 
 /* Controls */
 .sv__controls { display: flex; flex-wrap: wrap; gap: 10px; }
+.sv__mt-sm { margin-top: 12px; }
+.sv__instance-pick { display: flex; align-items: center; gap: 12px; }
+.sv__select {
+  background: var(--surface-base);
+  color: var(--text-primary);
+  border: none;
+  box-shadow: var(--ring-subtle);
+  border-radius: var(--radius-md);
+  padding: 8px 12px;
+  font-size: var(--text-sm);
+  font-family: var(--font-mono);
+  min-width: 280px;
+}
 
 /* Section head (label inside panel body) */
 .sv__section-head {