feat(briefing): UI polish for agentic briefing messages

Three visual improvements for the briefing conversation:

1. Intermediate tool-call messages (empty content, briefing_intermediate:
   true) now render as a compact dashed status row with per-tool pills
   showing result counts, instead of an empty assistant bubble followed
   by a stack of ToolCallCards. Click to expand the full cards.

2. Slot badge on non-intermediate briefing messages — "Full Briefing"
   for compilation, "Morning/Midday/Afternoon Update" for slot
   injections. Slot updates get a softer bubble treatment (transparent
   background, muted border, smaller text) so the compilation stays
   visually dominant.

3. Slot separator now triggers on briefing_slot metadata (not the
   compilation-only rss_item_ids), and uses a look-behind so it only
   fires when there's a prior slot message — no separator above the
   first briefing of the day.

New component: BriefingToolStatusRow.vue handles the intermediate
pill row and delegates to ToolCallCard when expanded.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/components/BriefingToolStatusRow.vue

@@ -0,0 +1,168 @@
+<script setup lang="ts">
+import { computed, ref } from "vue";
+import ToolCallCard from "@/components/ToolCallCard.vue";
+import type { ToolCallRecord } from "@/types/chat";
+
+const props = defineProps<{
+  toolCalls: ToolCallRecord[];
+}>();
+
+const expanded = ref(false);
+
+function shortName(fn: string): string {
+  return fn
+    .replace(/^(list|get|search|fetch)_/, "")
+    .replace(/_/g, " ");
+}
+
+interface Pill {
+  key: string;
+  name: string;
+  count: string | null;
+  state: "ok" | "empty" | "error";
+}
+
+const pills = computed<Pill[]>(() =>
+  props.toolCalls.map((tc, i) => {
+    const ok = tc.result?.success !== false && tc.status !== "error";
+    const data = tc.result?.data as Record<string, unknown> | undefined;
+    let count: string | null = null;
+    let state: Pill["state"] = ok ? "ok" : "error";
+    if (ok && data) {
+      const raw =
+        (typeof data.count === "number" && data.count) ||
+        (typeof data.total === "number" && data.total);
+      if (typeof raw === "number") {
+        count = String(raw);
+        if (raw === 0) state = "empty";
+      }
+    }
+    return {
+      key: `${tc.function}-${i}`,
+      name: shortName(tc.function),
+      count,
+      state,
+    };
+  }),
+);
+
+const errorCount = computed(() => pills.value.filter((p) => p.state === "error").length);
+</script>
+
+<template>
+  <div class="briefing-status" :class="{ expanded }">
+    <button class="briefing-status-toggle" @click="expanded = !expanded">
+      <span class="briefing-status-label">Gathered</span>
+      <span
+        v-for="p in pills"
+        :key="p.key"
+        class="briefing-status-pill"
+        :class="`state-${p.state}`"
+      >
+        {{ p.name }}<span v-if="p.count != null" class="pill-count">{{ p.count }}</span>
+      </span>
+      <span v-if="errorCount" class="briefing-status-errcount">{{ errorCount }} failed</span>
+      <span class="briefing-status-chevron" :class="{ open: expanded }">▶</span>
+    </button>
+    <div v-if="expanded" class="briefing-status-detail">
+      <ToolCallCard
+        v-for="(tc, i) in toolCalls"
+        :key="i"
+        :tool-call="tc"
+      />
+    </div>
+  </div>
+</template>
+
+<style scoped>
+.briefing-status {
+  margin: 0.25rem 0 0.5rem;
+  max-width: 80%;
+}
+
+.briefing-status-toggle {
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: 0.35rem;
+  width: 100%;
+  padding: 0.35rem 0.55rem;
+  background: transparent;
+  border: 1px dashed var(--color-border);
+  border-radius: 8px;
+  cursor: pointer;
+  font: inherit;
+  color: var(--color-text-muted);
+  transition: border-color 0.15s, background 0.15s;
+}
+.briefing-status-toggle:hover {
+  border-color: var(--color-primary);
+  background: color-mix(in srgb, var(--color-primary) 4%, transparent);
+}
+
+.briefing-status-label {
+  font-family: 'Fraunces', Georgia, serif;
+  font-style: italic;
+  font-size: 0.78rem;
+  color: var(--color-primary);
+  opacity: 0.85;
+  margin-right: 0.15rem;
+}
+
+.briefing-status-pill {
+  display: inline-flex;
+  align-items: center;
+  gap: 0.25rem;
+  padding: 0.08rem 0.45rem;
+  font-size: 0.72rem;
+  line-height: 1.45;
+  border-radius: 999px;
+  border: 1px solid var(--color-border);
+  color: var(--color-text-secondary);
+  background: var(--color-bg-card);
+  white-space: nowrap;
+}
+.briefing-status-pill.state-empty {
+  opacity: 0.55;
+}
+.briefing-status-pill.state-error {
+  border-color: color-mix(in srgb, var(--color-danger, #ef4444) 60%, var(--color-border));
+  color: var(--color-danger, #ef4444);
+}
+
+.pill-count {
+  font-weight: 600;
+  font-variant-numeric: tabular-nums;
+  padding: 0 0.25rem;
+  border-radius: 4px;
+  background: color-mix(in srgb, var(--color-primary) 12%, transparent);
+  color: var(--color-text);
+}
+.state-error .pill-count {
+  background: color-mix(in srgb, var(--color-danger, #ef4444) 18%, transparent);
+}
+
+.briefing-status-errcount {
+  font-size: 0.7rem;
+  color: var(--color-danger, #ef4444);
+  font-weight: 600;
+}
+
+.briefing-status-chevron {
+  margin-left: auto;
+  font-size: 0.65rem;
+  opacity: 0.5;
+  transition: transform 0.15s;
+}
+.briefing-status-chevron.open {
+  transform: rotate(90deg);
+}
+
+.briefing-status-detail {
+  margin-top: 0.4rem;
+  padding-left: 0.55rem;
+  display: flex;
+  flex-direction: column;
+  gap: 0.3rem;
+}
+</style>