feat: global activity feed + session digest

Ops "Executions" tab showed raw target UUIDs, alphabetical (not
recency) order, and a stale status vocabulary from an earlier schema
iteration — never actually usable as a live "what's happening" view.
Replaced with a new recency-ordered /api/v1/activity/recent endpoint
and matching table (human-readable action summaries, risk/status
badges, duration, inline error preview).

Also added /api/v1/activity/session/{id} + a collapsible SessionDigest
panel in the chat rail, answering "what did this session actually do"
(executions by status, entities touched, knowledge written) — the
missing piece for proactive outcome reporting to be visible in the UI,
not just in the chat transcript.

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

web/src/lib/api.ts

@@ -242,6 +242,41 @@ export async function cancelExecution(id: string): Promise<Execution | null> {
   return res.json()
 }
 
+export interface ActivityItem {
+  id: string
+  target: string
+  verb: string
+  summary: string
+  risk_class: string
+  status: string
+  duration_ms: number | null
+  error?: string
+  created_at: string
+  completed_at: string | null
+}
+
+export async function fetchRecentActivity(limit = 50): Promise<ActivityItem[]> {
+  const res = await fetch(`${API}/activity/recent?limit=${limit}`)
+  if (!res.ok) return []
+  const data = await res.json()
+  return data.items ?? []
+}
+
+export interface SessionDigest {
+  session_id: string
+  total_executions: number
+  by_status: Record<string, number>
+  entities_touched: string[]
+  executions: { target: string; verb: string; summary: string; risk_class: string; status: string }[]
+  knowledge_created: string[]
+}
+
+export async function fetchSessionDigest(sessionId: string): Promise<SessionDigest | null> {
+  const res = await fetch(`${API}/activity/session/${sessionId}`)
+  if (!res.ok) return null
+  return res.json()
+}
+
 export interface Signal {
   id: string
   slug: string

web/src/lib/components/SessionDigest.svelte

@@ -0,0 +1,100 @@
+<script lang="ts">
+  import { fetchSessionDigest, type SessionDigest } from '$lib/api'
+  import { currentSession, streaming } from '$lib/stores/chat'
+  import { Badge } from '$lib/components/ui/badge'
+  import ChevronDownIcon from '@lucide/svelte/icons/chevron-down'
+  import ChevronRightIcon from '@lucide/svelte/icons/chevron-right'
+  import SparklesIcon from '@lucide/svelte/icons/sparkles'
+
+  let digest = $state<SessionDigest | null>(null)
+  let open = $state(false)
+  let loadedFor = $state<string | null>(null)
+
+  // Reload the digest whenever the session changes or a stream finishes —
+  // "what did this session actually do" is only meaningful once executions
+  // have had a chance to land.
+  $effect(() => {
+    const sid = $currentSession
+    const busy = $streaming
+    if (!sid || busy) return
+    if (loadedFor === sid) return
+    loadedFor = sid
+    fetchSessionDigest(sid).then((d) => (digest = d))
+  })
+
+  function statusVariant(status: string): 'default' | 'secondary' | 'destructive' | 'outline' {
+    if (['failed', 'denied', 'revoked', 'cancelled'].includes(status)) return 'destructive'
+    if (status === 'completed') return 'default'
+    if (['running', 'approved'].includes(status)) return 'secondary'
+    return 'outline'
+  }
+</script>
+
+{#if digest && digest.total_executions > 0}
+  <div class="border-b">
+    <button
+      type="button"
+      class="flex w-full items-center justify-between gap-2 px-3 py-2 text-left text-xs font-medium hover:bg-muted/50"
+      onclick={() => (open = !open)}
+    >
+      <span class="flex items-center gap-1.5">
+        {#if open}<ChevronDownIcon class="size-3.5" />{:else}<ChevronRightIcon class="size-3.5" />{/if}
+        This session
+      </span>
+      <span class="flex items-center gap-1.5 text-muted-foreground">
+        {digest.total_executions} action{digest.total_executions === 1 ? '' : 's'}
+        {#if digest.knowledge_created.length}
+          <span class="flex items-center gap-0.5 text-primary">
+            <SparklesIcon class="size-3" />{digest.knowledge_created.length}
+          </span>
+        {/if}
+      </span>
+    </button>
+
+    {#if open}
+      <div class="flex flex-col gap-3 px-3 pb-3 text-xs">
+        <div class="flex flex-wrap gap-1">
+          {#each Object.entries(digest.by_status) as [status, count]}
+            <Badge variant={statusVariant(status)}>{status} × {count}</Badge>
+          {/each}
+        </div>
+
+        {#if digest.entities_touched.length}
+          <div>
+            <div class="mb-1 text-muted-foreground">Entities touched</div>
+            <div class="flex flex-wrap gap-1">
+              {#each digest.entities_touched as target}
+                <span class="rounded bg-muted px-1.5 py-0.5 font-mono text-[11px]">{target}</span>
+              {/each}
+            </div>
+          </div>
+        {/if}
+
+        <div class="flex flex-col gap-1">
+          {#each digest.executions as ex}
+            <div class="flex items-start justify-between gap-2 rounded border px-2 py-1">
+              <div class="min-w-0">
+                <div class="font-mono text-[11px] text-muted-foreground">{ex.target}</div>
+                <div class="truncate">{ex.summary || ex.verb}</div>
+              </div>
+              <Badge variant={statusVariant(ex.status)} class="shrink-0">{ex.status}</Badge>
+            </div>
+          {/each}
+        </div>
+
+        {#if digest.knowledge_created.length}
+          <div>
+            <div class="mb-1 flex items-center gap-1 text-primary">
+              <SparklesIcon class="size-3" />Learned this session
+            </div>
+            <ul class="list-inside list-disc">
+              {#each digest.knowledge_created as title}
+                <li>{title}</li>
+              {/each}
+            </ul>
+          </div>
+        {/if}
+      </div>
+    {/if}
+  </div>
+{/if}