feat: add diagram component board

[aidenybai]

Summary

• Add a minimal Next.js / StyleX SVG component board in packages/diagram
• Share compact primitives across static and 10,000-node virtualized trees
• Link parent/owner views, boundary catch regions, and provider-hover scopes
• Add a persistent, borderless Lucide sun/moon theme switch
• Add directed dataflow diagrams for useState, useReducer, useSyncExternalStore, useContext, derived values, props, callbacks, and host outputs
• Follow incoming/outgoing dependency paths on hover or keyboard focus, including cyclic store subscriptions

Dataflow is an explicit illustrative model, not automatic runtime instrumentation.

Validation

• Formatting, typecheck, lint, and production build pass
• 22 unit tests and 14 browser tests pass
• Light/dark, mobile overflow, linked hover, scope visibility, and virtual-row hitboxes covered

[changeset-bot]

⚠️ No Changeset found

Latest commit: b15543c

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated
bippy	Ready	Preview	Sep 6, 2026 4:10pm UTC

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/bippy@114

commit: 06331be

[aidenybai]

Dataflow visual cleanup pushed:

• Remove structural branches that overlapped data wires
• Render callback props as hollow value ports; keep updater operations filled
• Use symmetric label clearances and circle-outline endpoints
• Reduce arrowheads and align their tips with the wire endpoint
• Add zoomed light/dark browser checks and routing unit tests

Validation: production build, typecheck, lint, 26 unit tests and 15 browser tests pass.

[aidenybai]

Replaced the standalone dataflow specimen with inline hook/prop rows in the linked parent and owner trees.

• Neutral metadata rows; one accent for the active dependency flow
• Shared hover/keyboard tracing across both projections
• Ownership/context/error overlays only when relevant
• Bounded curved links, separate subscription/notification lanes, and preserved 3px arrow clearance
• Hide metadata grouping branches during tracing to avoid overlapping the wires

Build, typecheck, lint, 29 unit tests, and 15 browser tests pass.