better filtering

[typeholes]

• Needs more filter options
• Ability to both search for start nodes and filter child nodes
• probably best to move the filter section to a modal
• savable filters with presets like "exclude lib and node_modules"

[typeholes]

I'm experimenting with making the persistent storage a sqlite database which would allow filtering to be done via sql where clauses. We'd still want a user friendly UI to generate those predicates behind the scenes. We may also want to expose the clauses in an editable UI component for power users.