links: [[ autocomplete in the note editor

Typing `[[` in a text note's body opens a title-suggestion menu from the
titles index. Arrow keys move the selection, Enter/Tab inserts `[[Title]]`
and places the caret after it, Esc dismisses just the menu (kept from
bubbling to the dialog's Esc-close), mouse hover/click also select. The
menu appears only while the caret sits inside an unclosed [[… token.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FRgehjoz7Yv8LkUfADxACm

frontend/src/components/NoteEditor.vue

@@ -87,6 +87,77 @@ async function openLink(link: { title: string; id: string | null }) {
   emit("navigate", created.id);
 }
 
+// --- [[ link autocomplete in the body textarea ---
+const linkMenu = ref(false);
+const linkQuery = ref("");
+const linkStart = ref(-1); // index of the `[[` that opened the current token
+const linkSelected = ref(0);
+
+const linkMatches = computed(() => {
+  const q = linkQuery.value.trim().toLowerCase();
+  return titles.items.filter((t) => t.title && t.title.toLowerCase().includes(q)).slice(0, 8);
+});
+
+// On every edit, check whether the caret sits inside an unclosed `[[…` token
+// and, if so, open the suggestion menu with the partial title as the query.
+function onBodyInput() {
+  const el = bodyInput.value;
+  if (!el) return;
+  const caret = el.selectionStart ?? 0;
+  const text = body.value.slice(0, caret);
+  const open = text.lastIndexOf("[[");
+  if (open === -1) {
+    linkMenu.value = false;
+    return;
+  }
+  const between = text.slice(open + 2);
+  if (between.includes("]") || between.includes("\n")) {
+    linkMenu.value = false;
+    return;
+  }
+  linkQuery.value = between;
+  linkStart.value = open;
+  linkSelected.value = 0;
+  linkMenu.value = true;
+}
+
+function insertLink(title: string) {
+  const el = bodyInput.value;
+  const caret = el?.selectionStart ?? body.value.length;
+  const before = body.value.slice(0, linkStart.value);
+  const after = body.value.slice(caret);
+  const insertion = `[[${title}]]`;
+  body.value = before + insertion + after;
+  linkMenu.value = false;
+  const pos = before.length + insertion.length;
+  void nextTick(() => {
+    el?.focus();
+    el?.setSelectionRange(pos, pos);
+  });
+}
+
+function onBodyKeydown(e: KeyboardEvent) {
+  if (!linkMenu.value || linkMatches.value.length === 0) return;
+  if (e.key === "ArrowDown") {
+    e.preventDefault();
+    linkSelected.value = Math.min(linkSelected.value + 1, linkMatches.value.length - 1);
+  } else if (e.key === "ArrowUp") {
+    e.preventDefault();
+    linkSelected.value = Math.max(linkSelected.value - 1, 0);
+  } else if (e.key === "Enter" || e.key === "Tab") {
+    const m = linkMatches.value[linkSelected.value];
+    if (m) {
+      e.preventDefault();
+      insertLink(m.title);
+    }
+  } else if (e.key === "Escape") {
+    // Close only the menu — don't let it bubble to the dialog's Esc-to-close.
+    e.preventDefault();
+    e.stopPropagation();
+    linkMenu.value = false;
+  }
+}
+
 const reminderLocal = computed(() => toLocalInput(liveNote.value.remind_at));
 
 function onReminderChange(e: Event) {
@@ -207,14 +278,37 @@ async function act(fn: () => Promise<void>) {
           placeholder="Title"
           class="w-full bg-transparent text-base font-semibold outline-none placeholder:text-neutral-400"
         />
-        <textarea
-          v-if="liveNote.kind === 'text'"
-          ref="bodyInput"
-          v-model="body"
-          rows="8"
-          placeholder="Take a note…"
-          class="w-full resize-none bg-transparent text-sm leading-relaxed outline-none placeholder:text-neutral-400"
-        />
+        <div v-if="liveNote.kind === 'text'" class="relative">
+          <textarea
+            ref="bodyInput"
+            v-model="body"
+            rows="8"
+            placeholder="Take a note…    ([[ to link a note)"
+            class="w-full resize-none bg-transparent text-sm leading-relaxed outline-none placeholder:text-neutral-400"
+            @input="onBodyInput"
+            @keydown="onBodyKeydown"
+          />
+          <ul
+            v-if="linkMenu && linkMatches.length"
+            class="absolute left-0 top-full z-10 mt-1 max-h-48 w-64 overflow-y-auto rounded-lg border border-neutral-200 bg-white p-1 shadow-lg dark:border-neutral-700 dark:bg-neutral-800"
+          >
+            <li v-for="(m, i) in linkMatches" :key="m.id">
+              <button
+                type="button"
+                class="flex w-full items-center rounded-md px-2 py-1.5 text-left text-sm"
+                :class="
+                  i === linkSelected
+                    ? 'bg-brand/15 text-brand-700 dark:text-brand'
+                    : 'hover:bg-neutral-100 dark:hover:bg-neutral-700'
+                "
+                @mousemove="linkSelected = i"
+                @mousedown.prevent="insertLink(m.title)"
+              >
+                <span class="truncate">{{ m.title }}</span>
+              </button>
+            </li>
+          </ul>
+        </div>
         <NoteChecklist v-else class="py-1" :note-id="liveNote.id" :items="liveNote.items" editable />
 
         <div v-if="labelList.length" class="flex flex-wrap gap-1.5 pt-1">