sync: Idea Genealogy + Quick Capture Overhaul

From private repo:

Idea Genealogy:
- Required edge explanations across UI/tools/API/MCP
- Inferred edge schema (category/type/confidence)
- Added part_of relationship type
- Connection UI chips (Made by / Part of / Came from / Related)

Quick Capture Overhaul:
- Jina.ai fallback for JS-rendered sites (Twitter, SPAs)
- Simplified UI: removed mode buttons, auto-detect input type
- Renamed to "Add Stuff", moved to top-right
- Auto-edge creation from description entities
- Increased content summary length (500→1500 chars)

Description Generation Fix:
- Simplified prompt to "what is this"
- Added link/dimensions context
- Better creator attribution

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/services/helpers/contextBuilder.ts

@@ -111,13 +111,18 @@ function parseMetadata(metadata: unknown): Record<string, any> {
   if (!metadata) return {};
   if (typeof metadata === 'string') {
     try {
-      return JSON.parse(metadata);
+      const parsed = JSON.parse(metadata);
+      if (parsed && typeof parsed === 'object') {
+        return parsed as Record<string, any>;
+      }
+      return {};
     } catch (error) {
       console.warn('Failed to parse node metadata JSON:', error);
       return {};
     }
   }
   if (typeof metadata === 'object') {
+    if (metadata === null) return {};
     return metadata as Record<string, any>;
   }
   return {};