group activity entries by plan step + remove inline renderers from chat

- Tool calls in Activity timeline are now tagged with current plan step
- Indented entries show which step they belong to
- Step tracking via update_plan_step(status=running) tool calls
- Removed inline tool renderers from chat (health summary, fleet snapshot, etc.)
  — all tool output now visible only in sidebar Activity timeline

web/src/pages/Chat.svelte

@@ -6,7 +6,6 @@
   import TaskContextPanel from '$lib/components/TaskContextPanel.svelte'
   import InlineApproval from '$lib/components/InlineApproval.svelte'
   import AgentIndicator from '$lib/components/AgentIndicator.svelte'
-  import { getToolRenderer } from '$lib/tool-renderers'
   import { Button } from '$lib/components/ui/button'
   import { Textarea } from '$lib/components/ui/textarea'
   import ArrowUpIcon from '@lucide/svelte/icons/arrow-up'
@@ -45,14 +44,6 @@
     scrolledUp = false
   }
 
-  const MAX_INLINE_CARDS = 5
-
-  function getInlineTools(msg: { tools: any[] }): any[] {
-    const matched = msg.tools.filter((t) => getToolRenderer(t))
-    if (matched.length <= MAX_INLINE_CARDS) return matched
-    return matched.slice(0, MAX_INLINE_CARDS)
-  }
-
   // Resizable right rail (session graph). Persisted so it survives reloads.
   const RAIL_MIN = 260
   const RAIL_MAX = 620
@@ -147,12 +138,6 @@
               <div class="max-w-[85%] rounded-2xl rounded-br-sm bg-primary px-4 py-2.5 text-sm text-primary-foreground whitespace-pre-wrap">{msg.text}</div>
             {:else}
               <div class="flex w-full flex-col gap-2">
-                {#each getInlineTools(msg) as tool (tool.id)}
-                  {@const renderer = getToolRenderer(tool)}
-                  {#if renderer}
-                    <renderer.component {tool} />
-                  {/if}
-                {/each}
                 {#if msg.text}
                   <div class="prose-chat max-w-none text-sm leading-relaxed">
                     <!-- eslint-disable-next-line svelte/no-at-html-tags — sanitized via DOMPurify -->