floorplan-panel: dismantle legacy SVG layers replaced by the registry

The Phase 5 / 6 migration moved 7 kinds (fence, column, spawn, item,
elevator, stair, roof) to the registry's `def.floorplan` path, but the
legacy SVG layers in `floorplan-panel.tsx` were left mounted with empty
entry arrays — dead code carrying ~3k lines of useless cost in the diff.

Removed:
 - `FloorplanGeometryLayer` (~1.7k lines): inline component rendering
   walls / slabs / ceilings / openings from `wallPolygons` /
   `slabPolygons` / `ceilingPolygons` / `openingsPolygons` — all
   permanently empty stubs after the migration. Wall / slab / ceiling
   / door / window now render via `FloorplanRegistryLayer`.
 - `FloorplanFenceLayer` (~265 lines): fence entries always empty
   post-migration; fence renders via the registry.
 - `FloorplanElevatorLayer` (~420 lines): elevator entries always
   empty post-migration.
 - `FloorplanNodeLayer` (~415 lines): rendered items / spawns / stairs.
   Items + spawns are registry-driven; stair only needed the in-flight
   preview, which is now mounted directly via `FloorplanStairLayer`
   (preserved as a sibling of the registry layer).
 - `FloorplanItemImage` (~40 lines): internal helper used only by
   `FloorplanNodeLayer`.
 - `floorplan-roof-layer.tsx` (113 lines): roof / roof-segment now
   registry-driven.

Net: -2,989 lines from `floorplan-panel.tsx`, plus the deleted roof
layer file. The remaining 14k-line monolith still owns the orchestration
state (selection lookups, marquee, helper lifecycles, hit-test plumbing)
— that's a separate teardown.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

packages/editor/src/components/editor-2d/renderers/floorplan-roof-layer.tsx

@@ -1,113 +0,0 @@
-'use client'
-
-import type { Point2D, RoofNode, RoofSegmentNode } from '@pascal-app/core'
-import { memo } from 'react'
-import { toSvgX, toSvgY } from '../svg-paths'
-
-type FloorplanLineSegment = {
-  start: Point2D
-  end: Point2D
-}
-
-type FloorplanRoofSegmentEntry = {
-  segment: RoofSegmentNode
-  points: string
-  ridgeLine: FloorplanLineSegment | null
-}
-
-type FloorplanRoofEntry = {
-  roof: RoofNode
-  segments: FloorplanRoofSegmentEntry[]
-}
-
-type FloorplanRoofPalette = {
-  roofFill: string
-  roofActiveFill: string
-  roofSelectedFill: string
-  roofStroke: string
-  roofActiveStroke: string
-  roofSelectedStroke: string
-  roofRidgeStroke: string
-  roofSelectedRidgeStroke: string
-}
-
-type FloorplanRoofLayerProps = {
-  highlightedIdSet: ReadonlySet<string>
-  palette: FloorplanRoofPalette
-  roofEntries: FloorplanRoofEntry[]
-  selectedIdSet: ReadonlySet<string>
-}
-
-export const FloorplanRoofLayer = memo(function FloorplanRoofLayer({
-  highlightedIdSet,
-  palette,
-  roofEntries,
-  selectedIdSet,
-}: FloorplanRoofLayerProps) {
-  if (roofEntries.length === 0) {
-    return null
-  }
-
-  return (
-    <>
-      {roofEntries.map(({ roof, segments }) => {
-        const roofSelected = selectedIdSet.has(roof.id)
-        const roofHighlighted = highlightedIdSet.has(roof.id)
-        const hasSelectedSegment = segments.some(({ segment }) => selectedIdSet.has(segment.id))
-        const hasHighlightedSegment = segments.some(({ segment }) =>
-          highlightedIdSet.has(segment.id),
-        )
-        const isRoofActive =
-          roofSelected || roofHighlighted || hasSelectedSegment || hasHighlightedSegment
-
-        return (
-          <g key={roof.id} pointerEvents="none">
-            {segments.map(({ points, ridgeLine, segment }) => {
-              const isSegmentSelected = selectedIdSet.has(segment.id)
-              const isSegmentHighlighted = highlightedIdSet.has(segment.id)
-              const isSegmentActive = isSegmentSelected || isSegmentHighlighted
-
-              return (
-                <g key={segment.id}>
-                  <polygon
-                    fill={
-                      isSegmentActive
-                        ? palette.roofSelectedFill
-                        : isRoofActive
-                          ? palette.roofActiveFill
-                          : palette.roofFill
-                    }
-                    points={points}
-                    stroke={
-                      isSegmentActive
-                        ? palette.roofSelectedStroke
-                        : isRoofActive
-                          ? palette.roofActiveStroke
-                          : palette.roofStroke
-                    }
-                    strokeWidth={isSegmentActive ? '2.25' : isRoofActive ? '1.75' : '1.1'}
-                    vectorEffect="non-scaling-stroke"
-                  />
-                  {ridgeLine ? (
-                    <line
-                      fill="none"
-                      stroke={
-                        isSegmentActive ? palette.roofSelectedRidgeStroke : palette.roofRidgeStroke
-                      }
-                      strokeWidth={isSegmentActive ? '2' : '1.4'}
-                      vectorEffect="non-scaling-stroke"
-                      x1={toSvgX(ridgeLine.start.x)}
-                      x2={toSvgX(ridgeLine.end.x)}
-                      y1={toSvgY(ridgeLine.start.y)}
-                      y2={toSvgY(ridgeLine.end.y)}
-                    />
-                  ) : null}
-                </g>
-              )
-            })}
-          </g>
-        )
-      })}
-    </>
-  )
-})