feat(web+nomos): fix chat streaming reactivity, unified activity timeline, tool cards in chat

- fix(web): Svelte 5 identity-based reactivity broke text_delta streaming —
  immutable message objects in all three chat handlers so text streams live
- feat(web): streaming cursor + inline status indicator merged into message flow
- feat(web): expandable inline tool call cards in chat thread
- feat(web): merge Plan + Event log into one backbone Activity timeline —
  filled status nodes, branch stubs, auto-scroll follow mode, per-session
  activityLog, compact for the rail
- fix(nomos): add X-Accel-Buffering:no to /chat SSE (proxy buffering)
- fix(nomos): plan step auto-close SQL param bug (store.go)
- polish: timestamps, role labels, code copy button, table overflow, min
  window size, delete AgentIndicator/ActivityTimeline dead code

web/src/lib/components/ToolCallCard.svelte

@@ -0,0 +1,85 @@
+<script lang="ts">
+  import { Check, ChevronRight, Loader2, Wrench, X } from '@lucide/svelte'
+  import type { ToolCallResult } from '$lib/types'
+
+  let { tool }: { tool: ToolCallResult } = $props()
+  let expanded = $state(false)
+
+  const status = $derived.by(() => {
+    if (tool.type === 'tool_use') return 'running'
+    if (tool.error) return 'error'
+    return 'done'
+  })
+
+  const statusColor = $derived.by(() => {
+    if (status === 'running') return 'text-primary'
+    if (status === 'error') return 'text-destructive'
+    return 'text-success/60'
+  })
+
+  const argsSummary = $derived.by(() => {
+    if (!tool.args) return ''
+    const entries = Object.entries(tool.args)
+    if (entries.length === 0) return ''
+    const first = entries[0]
+    const val = typeof first[1] === 'string' ? first[1] : JSON.stringify(first[1])
+    return `${first[0]}: ${val.length > 60 ? val.slice(0, 60) + '…' : val}`
+  })
+</script>
+
+<div class="tool-card rounded-lg border border-border/60 bg-card/40 overflow-hidden transition-all">
+  <button
+    class="flex w-full items-center gap-2 px-3 py-2 text-left hover:bg-muted/40 transition-colors"
+    onclick={() => (expanded = !expanded)}
+    aria-expanded={expanded}
+  >
+    <ChevronRight class="size-3 shrink-0 text-muted-foreground transition-transform {expanded ? 'rotate-90' : ''}" />
+    <Wrench class="size-3.5 shrink-0 text-muted-foreground" />
+    <span class="font-mono text-xs font-medium text-foreground/80">{tool.name}</span>
+    {#if argsSummary}
+      <span class="ml-1 truncate text-[11px] text-muted-foreground/70">{argsSummary}</span>
+    {/if}
+    <span class="ml-auto shrink-0 {statusColor}">
+      {#if status === 'running'}
+        <Loader2 class="size-3.5 animate-spin" />
+      {:else if status === 'error'}
+        <X class="size-3.5" />
+      {:else}
+        <Check class="size-3.5" />
+      {/if}
+    </span>
+  </button>
+
+  {#if expanded}
+    <div class="border-t border-border/40 px-3 py-2 space-y-2">
+      {#if tool.args}
+        <div>
+          <div class="text-[10px] font-semibold uppercase tracking-wider text-muted-foreground mb-1">Args</div>
+          <pre class="tool-pre rounded-md bg-muted/60 p-2 text-[11px] overflow-x-auto max-h-48">{JSON.stringify(tool.args, null, 2)}</pre>
+        </div>
+      {/if}
+      {#if tool.result !== undefined && tool.result !== null}
+        <div>
+          <div class="text-[10px] font-semibold uppercase tracking-wider text-muted-foreground mb-1">Result</div>
+          <pre class="tool-pre rounded-md bg-muted/60 p-2 text-[11px] overflow-x-auto max-h-48">{JSON.stringify(tool.result, null, 2)}</pre>
+        </div>
+      {/if}
+      {#if tool.error}
+        <div>
+          <div class="text-[10px] font-semibold uppercase tracking-wider text-destructive mb-1">Error</div>
+          <pre class="tool-pre rounded-md bg-destructive/5 border border-destructive/20 p-2 text-[11px] text-destructive overflow-x-auto max-h-48">{tool.error}</pre>
+        </div>
+      {/if}
+    </div>
+  {/if}
+</div>
+
+<style>
+  .tool-card {
+    animation: tool-in 0.2s ease-out;
+  }
+  @keyframes tool-in {
+    from { opacity: 0; transform: translateY(-2px); }
+    to { opacity: 1; transform: translateY(0); }
+  }
+</style>