What does this PR do?

Exports the thin editor-side glue that lets embedders compose <Viewer> + the interaction layer directly, without mounting the full <Editor> chrome — the registry already owns the per-kind tools (def.tool / def.affordanceTools / def.floorplanAffordances); these exports are the router and hosts around it:

• ToolManager — the tool router (registry-driven + legacy fallbacks)
• useKeyboard — the global shortcut hook (alongside the already-public markToolCancelConsumed)
• CustomCameraControls — orbit/pan/first-person camera glue
• getRegistryAffordanceTool — the def.affordanceTools dispatcher
• BoxSelectTool — screen-space marquee selection
• CeilingSystem, CeilingSelectionAffordanceSystem, RoofEditSystem, StairEditSystem, ZoneSystem — edit-affordance systems
• Phase type (joins the already-exported Tool type from store/use-editor)

Additive only — no behavior change, no signature change, no file moves. Follows the same embedder story as layoutVersion, the v2 slot props, and the recent Phase 5 Stage D/E export waves: we build a custom shell on @pascal-app/editor and currently must choose between mounting all of <Editor>'s chrome or forking these files; with these exports we can compose Viewer + ToolManager + CustomCameraControls + useKeyboard (+ systems) and own the chrome while every kind-owned tool keeps working untouched.

How to test

1. bun install && bun run build (or turbo run build --filter='@pascal-app/*') — builds green.
2. cd packages/editor && bun run check-types — clean (verified locally).
3. bunx biome check packages/editor/src/index.tsx — clean (verified locally).
4. Consumer smoke (optional): in any app depending on @pascal-app/editor, import { ToolManager, useKeyboard, CustomCameraControls, Phase } from '@pascal-app/editor' resolves and <Viewer><ToolManager/><CustomCameraControls/></Viewer> mounts the registry tools.

Screenshots / screen recording

N/A — non-visual change (barrel exports only).

Checklist

• I've tested this locally with bun dev (verified via package typecheck + workspace build instead; no app run)
• My code follows the existing code style (run bun check to verify)
• I've updated relevant documentation (if applicable)
• This PR targets the main branch