feat(web): redesign task rail — Plan/Event log polish, entity graph resize fix

- Plan/Activity panels: humanize step titles, richer icons, empty states
  matching Scope's illustration style, pretty-printed expandable detail
- Activity log renamed to Event log; every step now expandable
- Chat: middle-truncate header title, remove redundant task-list rail and
  header stat cluster (duplicated in the sidebar), simplify markdown styling
- Fix --font-mono actually being a monospace font (was aliased to DM Sans)
- Replace rotating loader-circle spinner with a smoother fading-blade Spinner
- SessionGraph entity detail panel: resizable and self-clamping against its
  live container size (was overflowing into sibling sections), close button
- Dev launch config: fetch bearer token from the running api container so
  `npm run dev` works against the local compose stack without a hardcoded
  secret in a tracked file

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

web/src/lib/components/SessionDigest.svelte

@@ -9,7 +9,7 @@
   import CircleCheckIcon from '@lucide/svelte/icons/circle-check'
   import CircleXIcon from '@lucide/svelte/icons/circle-x'
   import CircleIcon from '@lucide/svelte/icons/circle'
-  import LoaderCircleIcon from '@lucide/svelte/icons/loader-circle'
+  import Spinner from './Spinner.svelte'
   import WrenchIcon from '@lucide/svelte/icons/wrench'
 
   let digest = $state<SessionDigest | null>(null)
@@ -76,7 +76,7 @@
 
 {#if $streaming && $currentSession}
   <div class="flex items-center gap-2 border-b px-3 py-2 text-xs text-muted-foreground">
-    <LoaderCircleIcon class="size-3 shrink-0 animate-spin text-primary" />
+    <Spinner class="size-3 shrink-0 text-primary" />
     <span>{toolCount} tool{toolCount === 1 ? '' : 's'} · {runningCount} running</span>
   </div>
 {/if}
@@ -114,7 +114,7 @@
             {#if step.status === 'done'}
               <CircleCheckIcon class="size-3 text-success" />
             {:else if step.status === 'running'}
-              <LoaderCircleIcon class="size-3 animate-spin text-primary" />
+              <Spinner class="size-3 text-primary" />
             {:else if step.status === 'failed'}
               <CircleXIcon class="size-3 text-destructive" />
             {:else}
@@ -155,7 +155,7 @@
                   {:else if t.type === 'tool_result'}
                     <CircleCheckIcon class="size-3 text-success" />
                   {:else}
-                    <LoaderCircleIcon class="size-3 animate-spin text-primary" />
+                    <Spinner class="size-3 text-primary" />
                   {/if}
                 </span>
                 <span class="font-mono text-[10px] truncate">{toolSummary(t)}</span>