Add LLM tool calling for creating tasks, notes, and searching from chat

Ollama tool/function calling integration allows the LLM to create tasks,
create notes, and search existing notes on behalf of the user during chat.
Multi-round tool loop (max 5 rounds) lets the model execute tools then
produce a natural language response. Tool results are persisted in a new
JSONB column on messages and rendered as compact cards with linked titles.

- Migration 0013: add tool_calls JSONB column to messages
- New services/tools.py: tool definitions + execute_tool dispatcher
- llm.py: ChatChunk dataclass, stream_chat_with_tools(), date in system prompt
- generation_task.py: multi-round tool call loop with SSE tool_call events
- Frontend: ToolCallRecord type, streamingToolCalls in store, ToolCallCard
  component, rendering in ChatMessage and ChatView streaming bubble

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

frontend/src/components/ChatMessage.vue

@@ -2,6 +2,7 @@
 import { computed } from "vue";
 import { renderMarkdown } from "@/utils/markdown";
 import { useSettingsStore } from "@/stores/settings";
+import ToolCallCard from "@/components/ToolCallCard.vue";
 import type { Message } from "@/types/chat";
 
 const settingsStore = useSettingsStore();
@@ -48,6 +49,13 @@ const roleLabel = computed(() => {
           </div>
         </div>
         <div class="message-content prose" v-html="rendered"></div>
+        <div v-if="message.tool_calls?.length" class="tool-calls">
+          <ToolCallCard
+            v-for="(tc, i) in message.tool_calls"
+            :key="i"
+            :tool-call="tc"
+          />
+        </div>
         <div
           v-if="message.context_note_id"
           class="context-badge"
@@ -157,6 +165,12 @@ const roleLabel = computed(() => {
   color: #fff;
   border-color: var(--color-primary);
 }
+.tool-calls {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 0.3rem;
+  margin-top: 0.4rem;
+}
 .context-badge {
   margin-top: 0.4rem;
   font-size: 0.75rem;

frontend/src/components/ToolCallCard.vue

@@ -0,0 +1,124 @@
+<script setup lang="ts">
+import { computed } from "vue";
+import type { ToolCallRecord } from "@/types/chat";
+
+const props = defineProps<{
+  toolCall: ToolCallRecord;
+}>();
+
+const label = computed(() => {
+  if (!props.toolCall.result.success) return "Error";
+  switch (props.toolCall.result.type) {
+    case "task":
+      return "Created task";
+    case "note":
+      return "Created note";
+    case "search":
+      return "Searched notes";
+    default:
+      return "Tool call";
+  }
+});
+
+const title = computed(() => {
+  const data = props.toolCall.result.data;
+  if (!data) return null;
+  if (typeof data.title === "string") return data.title;
+  return null;
+});
+
+const linkTo = computed(() => {
+  const data = props.toolCall.result.data;
+  if (!data || typeof data.id !== "number") return null;
+  return `/notes/${data.id}`;
+});
+
+const searchResults = computed(() => {
+  const data = props.toolCall.result.data;
+  if (!data || props.toolCall.result.type !== "search") return null;
+  const results = data.results as Array<{ id: number; title: string; type: string }> | undefined;
+  return results && results.length > 0 ? results : null;
+});
+</script>
+
+<template>
+  <div class="tool-call-card" :class="{ error: toolCall.status === 'error' }">
+    <span class="tool-label">{{ label }}</span>
+    <template v-if="toolCall.status === 'error'">
+      <span class="tool-error">{{ toolCall.result.error }}</span>
+    </template>
+    <template v-else-if="searchResults">
+      <span class="tool-search-info">{{ (toolCall.result.data?.total as number) ?? 0 }} found</span>
+      <div class="tool-search-results">
+        <router-link
+          v-for="r in searchResults"
+          :key="r.id"
+          :to="`/notes/${r.id}`"
+          class="tool-search-item"
+        >
+          {{ r.title || "Untitled" }}
+        </router-link>
+      </div>
+    </template>
+    <template v-else-if="linkTo">
+      <router-link :to="linkTo" class="tool-link">{{ title }}</router-link>
+    </template>
+  </div>
+</template>
+
+<style scoped>
+.tool-call-card {
+  display: inline-flex;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: 0.35rem;
+  background: var(--color-bg-secondary);
+  border: 1px solid var(--color-border);
+  border-radius: 12px;
+  padding: 0.3rem 0.6rem;
+  font-size: 0.8rem;
+  margin-top: 0.4rem;
+}
+.tool-call-card.error {
+  border-color: var(--color-danger, #e74c3c);
+}
+.tool-label {
+  font-weight: 600;
+  color: var(--color-text-muted);
+  text-transform: uppercase;
+  letter-spacing: 0.03em;
+  font-size: 0.7rem;
+}
+.tool-link {
+  color: var(--color-primary);
+  text-decoration: none;
+}
+.tool-link:hover {
+  text-decoration: underline;
+}
+.tool-error {
+  color: var(--color-danger, #e74c3c);
+}
+.tool-search-info {
+  color: var(--color-text-muted);
+}
+.tool-search-results {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 0.25rem;
+  width: 100%;
+}
+.tool-search-item {
+  color: var(--color-primary);
+  text-decoration: none;
+  font-size: 0.8rem;
+}
+.tool-search-item:hover {
+  text-decoration: underline;
+}
+.tool-search-item:not(:last-child)::after {
+  content: ",";
+  color: var(--color-text-muted);
+  margin-right: 0.1rem;
+}
+</style>