feat: add Ctrl+F search panel for finding nodes and edges

[avinxshKD]

fixes #356

Ctrl+F did nothing. In a 40-node graph you're just panning and squinting. Every other graph tool has this.

Wired up a floating search panel, Ctrl+F opens it, type to filter, Enter/Shift+Enter cycles matches, Esc closes and restores. Matches get an orange overlay, everything else dims. Counter shows 3 of 12. Viewport pans to each result via cytoscape's animate.

Touches:

SearchPanel.jsx + css, the widget itself
tailored-graph-builder, searchElements, clearSearch, flyToElement
cytoscape-style, .search-match / .search-dim selectors
reducer, 4 new keys (searchPanel, searchQuery, searchResults, searchIndex)
toolbar, Search button, Ctrl+F hotkey

Before: ctrl+f did nothing

After: matches highlight, rest dims, cycles through with enter

[avinxshKD]

@pradeeban hope you like this one, search state lives in the reducer, highlight/dim goes through cytoscape classes so it doesn't touch any graph data. let me know if you want me to scope it differentlyy :p

[pradeeban]

Your other merged PR has now created a merge conflict. Pls resolve. I like the PR. Minimal and on-point.

[avinxshKD]

@pradeeban done, glad it landed well, kept it label-only to stay minimal for v1