feat: surface blast radius on approval cards

Pending-approval cards showed target and risk but not what else the
action would affect — the operator approved config_mutation/destructive
commands blind to downstream impact, even though the graph-walk
(blast_radius() SQL, GetBlastRadius endpoint) already existed and was
just never wired into the approval path.

Fetch it once per pending approval and render "Affects N downstream: …"
on both the normal and destructive approval cards, reusing the existing
fetchBlastRadius() API client function which was already written but
unused anywhere.

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

web/src/lib/components/InlineApproval.svelte

@@ -1,15 +1,30 @@
 <script lang="ts">
   import type { PendingApproval } from '$lib/stores/chat'
-  import { decideApproval, getExecution, type Execution } from '$lib/api'
+  import { decideApproval, getExecution, fetchBlastRadius, type Execution } from '$lib/api'
   import { Button } from '$lib/components/ui/button'
   import { SvelteMap } from 'svelte/reactivity'
   import CheckIcon from '@lucide/svelte/icons/check'
   import XIcon from '@lucide/svelte/icons/x'
   import ShieldCheckIcon from '@lucide/svelte/icons/shield-check'
   import LoaderCircleIcon from '@lucide/svelte/icons/loader-circle'
+  import NetworkIcon from '@lucide/svelte/icons/network'
 
   let { approvals }: { approvals: PendingApproval[] } = $props()
 
+  // Downstream entities the target affects, keyed by executionId — fetched
+  // once per approval so the operator sees the graph-walk impact ("this
+  // affects 3 downstream") before deciding, not after. depth 0 is the target
+  // itself, excluded here since it's already shown as "on {target}".
+  const blastRadius = new SvelteMap<string, string[]>()
+  const blastRadiusFetched = new Set<string>()
+  async function loadBlastRadius(a: PendingApproval) {
+    if (blastRadiusFetched.has(a.executionId) || a.target === 'unknown') return
+    blastRadiusFetched.add(a.executionId)
+    const items = await fetchBlastRadius(a.target)
+    const affected = items.filter((i) => i.depth > 0).map((i) => i.entity.slug)
+    if (affected.length) blastRadius.set(a.executionId, affected)
+  }
+
   // Per-execution UI phase, keyed by executionId. A resolved phase hides the
   // action buttons permanently so the banner clears after a click and can
   // never re-POST /decision.
@@ -125,7 +140,10 @@
 
   $effect(() => {
     for (const a of approvals) {
-      if (!phase.get(a.executionId)) void watchExternal(a.executionId)
+      if (!phase.get(a.executionId)) {
+        void watchExternal(a.executionId)
+        void loadBlastRadius(a)
+      }
     }
   })
 </script>
@@ -194,6 +212,7 @@
       </span>
     </div>
   {:else if approval.destructive}
+    {@const affected = blastRadius.get(approval.executionId)}
     <div class="my-2 flex flex-col gap-1 rounded-lg border border-destructive/50 bg-destructive/10 px-3 py-2">
       <div class="flex items-center gap-2">
         <ShieldCheckIcon class="size-4 shrink-0 text-destructive" />
@@ -211,9 +230,17 @@
       {#if approval.command}
         <code class="ml-6 block truncate text-xs text-destructive/80">{approval.command}</code>
       {/if}
+      {#if affected}
+        <div class="ml-6 flex items-start gap-1.5 text-xs text-destructive/90">
+          <NetworkIcon class="mt-0.5 size-3 shrink-0" />
+          <span>Affects {affected.length} downstream: {affected.join(', ')}</span>
+        </div>
+      {/if}
     </div>
   {:else}
-    <div class="my-2 flex items-center gap-2 rounded-lg border border-warning/40 bg-warning/5 px-3 py-2">
+    {@const affected = blastRadius.get(approval.executionId)}
+    <div class="my-2 flex flex-col gap-1 rounded-lg border border-warning/40 bg-warning/5 px-3 py-2">
+      <div class="flex items-center gap-2">
         <ShieldCheckIcon class="size-4 shrink-0 text-warning" />
         <span class="flex-1 text-xs text-muted-foreground">{approval.action} on {approval.target} requires approval</span>
         <Button size="sm" variant="default" class="h-7 px-2.5 text-xs" onclick={() => decide(approval, 'approve')}>
@@ -223,5 +250,12 @@
           <XIcon class="size-3" /><span class="ml-1">Deny</span>
         </Button>
       </div>
+      {#if affected}
+        <div class="ml-6 flex items-start gap-1.5 text-xs text-warning">
+          <NetworkIcon class="mt-0.5 size-3 shrink-0" />
+          <span>Affects {affected.length} downstream: {affected.join(', ')}</span>
+        </div>
+      {/if}
+    </div>
   {/if}
 {/each}