M3 wiki-links: [[links]] + backlinks

- Migration 0009: note_links (source_id, target_norm). Parse [[...]] from body on
  create/update and rewrite the source's links. GET /api/notes/titles (owner
  {id,title} index for client-side resolution); GET /api/notes/<id>/backlinks.
- Frontend: titles store; LinkedText renders [[Title]] styled on cards; editor
  shows Links (outgoing, resolve/create-on-click) + Linked-from (backlinks),
  clicking navigates the editor to the target note (board + search).
- notes store: fetchOne, createTitled. DB-free link-parser tests.

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

frontend/src/components/LinkedText.vue

@@ -0,0 +1,36 @@
+<script setup lang="ts">
+import { computed } from "vue";
+
+const props = defineProps<{ text: string }>();
+
+interface Part {
+  text: string;
+  link: boolean;
+}
+
+// Split the body into plain segments and [[wiki-link]] segments (styled, non-
+// interactive here — navigation happens from the editor's Links / Linked-from
+// lists so we don't nest interactive controls inside the card's open target).
+const parts = computed<Part[]>(() => {
+  const result: Part[] = [];
+  const re = /\[\[([^[\]]+)\]\]/g;
+  let last = 0;
+  let match: RegExpExecArray | null;
+  while ((match = re.exec(props.text)) !== null) {
+    if (match.index > last) result.push({ text: props.text.slice(last, match.index), link: false });
+    result.push({ text: match[1].trim(), link: true });
+    last = match.index + match[0].length;
+  }
+  if (last < props.text.length) result.push({ text: props.text.slice(last), link: false });
+  return result;
+});
+</script>
+
+<template>
+  <span class="whitespace-pre-wrap break-words"
+    ><template v-for="(part, i) in parts" :key="i"
+      ><span v-if="part.link" class="font-medium text-brand-700 dark:text-brand">{{ part.text }}</span
+      ><template v-else>{{ part.text }}</template></template
+    ></span
+  >
+</template>