ANG-004: Structural note graph with Cytoscape.js + fCoSE webview rendering

[yugalkaushik]

Renders an interactive graph inside a Joplin panel showing explicit note-to-note links as solid arrowed edges and shared tag relationships as dotted edges.

• Bundled Cytoscape.js and fCoSE layout for the browser webview via a separate webpack config targeting web
• Built graph builder that assembles nodes and edges into Cytoscape-compatible format, computes degree for each node
• Added click-to-navigate: tapping a node opens the corresponding note in Joplin
• Styled connected nodes as blue circles with borders, link edges as solid with arrowheads, tag edges as dotted gray
• Added ResizeObserver so the graph fills the panel and adapts to resize
• Wrote unit tests for edge factory (9 tests) and graph builder (6 tests)

Preview