[Xoppyc]

Summary

Adds an interactive Element Inspector and cross-panel component funneling to the devtools dock.

Rather than only serving as a jump-to-editor utility, selecting an element activates a component funnel across the devtools panels:

1. Reactivity Graph: Isolates reactive signals, memos, and effects belonging to the selected component's owner instance hierarchy (instead of showing all global reactive nodes or broad name matches).
2. Ownership Tree: Automatically expands, reveals, and scrolls to the selected component node so its props and internal scopes can be inspected immediately.
3. Preserves Active Tab: Selecting an element keeps you on your current active panel (e.g. Reactivity) without jarring tab jumps, while displaying a funnel badge in the dock header.
4. Dock Header Funnel Badge: Shows the component name with a quick jump to the Ownership tree, a direct "See in editor" button (using Vite's /__open-in-editor), and a clear button (✕) to unfunnel.
5. Shortcuts & Activation:
   • Alt+Shift+C (or the crosshair icon in the dock header) toggles inspect mode.
   • Hovering DOM nodes displays an overlay badge with component name, file location, and dimensions.
   • Escape cancels inspection.

Technical Details

• Zero Additional Plugins: Relies exclusively on @solidjs/vite-plugin's dev-mode location injection (owner._component.fn.location) and Solid's runtime ownership tree.
• Robust DOM Lookup: Monkeypatches document.createElement / createElementNS in dev mode using a WeakMap<Node, Owner> to map real DOM nodes back to their originating Solid component owners without adding data-attributes to the user's DOM.
• Instance-Level Reactivity Filtering: ReactivityViewer filters nodes using isDescendantOf(node.owner, targetOwner) so multiple instances of identical components (like <For> iterations or reused UI components) are isolated accurately.
• Editor Launch Reliability: Handles nested monorepo / example subpath depths against Vite's launch-editor-middleware.

Verification

• Unit tests added for DOM-to-component lookup and traversal (src/dev-toolbar/inspector/lookup.test.ts).
• pnpm test (all 116 tests passing).
• pnpm typecheck (clean TypeScript check).
• pnpm format:check (oxfmt clean).
• pnpm build (clean rolldown bundle & DTS generation).
• Changeset included (.changeset/element-inspector.md).