feat: node view redesign — single-scroll, no tabs

Ports the full node view redesign from ra-h. Replaces the 4-tab layout
(Desc/Notes/Edges/Source) with a single-scroll document view.

- New FocusPanel: frontmatter rows, collapse toggle, NodeSearchModal,
  TipTap SourceEditor, section headers with extending rules
- NodeSearchModal: new full-screen portal modal for creating connections
- SourceEditor: TipTap WYSIWYG editor (new file)
- SourceReader: removed header chrome, added onContentClick prop
- Source formatters: inherit font, 15px/1.7, no max-width centering
- DimensionTags: subtle dashed + button replaces green pill
- autoEmbedQueue: recover nodes stuck in 'chunking' state on startup
- edges: fix extra parameter in getNodeConnectionsSQLite

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

src/services/database/edges.ts

@@ -522,7 +522,6 @@ export class EdgeService {
       nodeId,
       nodeId,
       nodeId,
-      nodeId,
       nodeId
     ]);