feat: proper wiki-links as custom BlockNote inline content with suggestion menu

- Custom 'wikilink' inline content type via createReactInlineContentSpec
- Extended BlockNote schema with wikilink spec
- Suggestion menu triggered by [[ showing all vault entries
- Markdown round-trip: [[target]] → placeholder tokens → wikilink inline content
- Click handler on .wikilink elements for navigation
- Removed old hack (regex preprocessing to wikilink.internal URLs + DOM click interception on <a> tags)
- Added .wikilink CSS styles
- Passed entries prop from App.tsx to Editor for suggestion menu

src/components/Editor.css

@@ -107,6 +107,22 @@
   color: var(--text-primary);
 }
 
+/* Wikilink inline content */
+.wikilink {
+  color: var(--accent-blue, #2196f3);
+  cursor: pointer;
+  text-decoration: underline;
+  text-decoration-style: dotted;
+  text-underline-offset: 2px;
+  border-radius: 2px;
+  padding: 0 1px;
+}
+
+.wikilink:hover {
+  background: var(--accent-blue-bg, rgba(33, 150, 243, 0.1));
+  text-decoration-style: solid;
+}
+
 /* BlockNote container */
 .editor__blocknote-container {
   flex: 1;