Drop wall + fence feature flags: register unconditionally; remove verification logs

Parity comparison against deployed prod is now cleaner than juggling
env-var flag toggles locally. Both kinds enter builtinPlugin.nodes
unconditionally; the Phase 0 dispatch shims (<LegacySystem kind="X">
wrappers + NodeRenderer's registry-first branch) handle the cutover.

Files deleted:
 - packages/nodes/src/wall/feature-flag.ts
 - packages/nodes/src/fence/feature-flag.ts

Files changed:
 - packages/nodes/src/index.ts: drops isWallRegistryEnabled /
   isFenceRegistryEnabled gates; wallDefinition + fenceDefinition
   land directly in builtinPlugin.nodes.
 - packages/nodes/src/{wall,fence}/index.ts: drop the flag re-export.
 - packages/nodes/src/{wall,fence}/renderer.tsx: drop the one-shot
   verification console.info. Same for the system.tsx wrappers.
 - packages/viewer/src/components/renderers/{wall,fence}/{wall,fence}-
   renderer.tsx: drop the paired [X:legacy] verification logs (no
   longer comparing flag-toggled paths).

Net DX: no env var to remember when starting `bun dev:community`. To
A/B test, compare against editor.pascal.app deployed prod.

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

packages/nodes/src/fence/feature-flag.ts

@@ -1,13 +0,0 @@
-/**
- * Feature flag for the registry-driven fence.
- *
- * Same pattern as wall (Phase 3) and spawn (Phase 2): with the flag on,
- * `fenceDefinition` is appended to `builtinPlugin.nodes` and the Phase 0
- * dispatch shims hand fence over to the registry. With the flag off,
- * the legacy fence paths run unchanged.
- *
- * Drops the moment Phase 5 fence parity is signed off.
- */
-export const isFenceRegistryEnabled = (): boolean => {
-  return process.env.NEXT_PUBLIC_USE_REGISTRY_FOR_FENCE === 'true'
-}

packages/nodes/src/fence/index.ts

@@ -1,3 +1,2 @@
 export { fenceDefinition } from './definition'
-export { isFenceRegistryEnabled } from './feature-flag'
 export { FenceNode } from './schema'

packages/nodes/src/fence/renderer.tsx

@@ -2,7 +2,7 @@
 
 import { type FenceNode, useRegistry, useScene } from '@pascal-app/core'
 import { DEFAULT_STAIR_MATERIAL, useNodeEvents } from '@pascal-app/viewer'
-import { useEffect, useLayoutEffect, useMemo, useRef } from 'react'
+import { useLayoutEffect, useMemo, useRef } from 'react'
 import type { Mesh } from 'three'
 
 /**
@@ -17,8 +17,6 @@ import type { Mesh } from 'three'
  * Material is `DEFAULT_STAIR_MATERIAL` (legacy reuse; fence and stairs
  * share the wood-tone preset).
  */
-let didLogFirstRegistryFenceMount = false
-
 const FenceRenderer = ({ node }: { node: FenceNode }) => {
   const ref = useRef<Mesh>(null!)
   const handlers = useNodeEvents(node, 'fence')
@@ -29,14 +27,6 @@ const FenceRenderer = ({ node }: { node: FenceNode }) => {
     useScene.getState().markDirty(node.id)
   }, [node.id])
 
-  useEffect(() => {
-    if (didLogFirstRegistryFenceMount) return
-    didLogFirstRegistryFenceMount = true
-    console.info(
-      '[fence:registry] first registry-driven FenceRenderer mounted — legacy FenceRenderer is NOT in use',
-    )
-  }, [])
-
   return (
     <mesh
       castShadow

packages/nodes/src/fence/system.tsx

@@ -1,7 +1,6 @@
 'use client'
 
 import { FenceSystem } from '@pascal-app/viewer'
-import { useEffect } from 'react'
 
 /**
  * Registry-driven fence system bundle.
@@ -10,8 +9,7 @@ import { useEffect } from 'react'
  * via `RegisteredSystems` when fence is registry-driven. The legacy
  * `<LegacySystem kind="fence">` wrapper around `<FenceSystem />` in
  * `viewer/components/viewer/index.tsx` short-circuits whenever
- * `nodeRegistry.has('fence')` is true — same pattern wall used in
- * milestone B.
+ * `nodeRegistry.has('fence')` is true — same pattern wall uses.
  *
  * Phase 6 deletes the legacy mount point; until then this bundle is the
  * single mount surface for fence's per-frame work when registry-driven.
@@ -22,13 +20,6 @@ import { useEffect } from 'react'
  * the rebuild loop and this bundle can be deleted.
  */
 const FenceSystems = () => {
-  useEffect(() => {
-    console.info('[fence:registry] system bundle mounted — registry path active')
-    return () => {
-      console.info('[fence:registry] system bundle unmounted')
-    }
-  }, [])
-
   return <FenceSystem />
 }