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/wall/system.tsx

@@ -1,12 +1,11 @@
 'use client'
 
 import { WallCutout, WallSystem } from '@pascal-app/viewer'
-import { useEffect } from 'react'
 
 /**
  * Registry-driven wall system bundle.
  *
- * Wall has two per-frame concerns that need to mount when the kind is
+ * Wall has two per-frame concerns that mount when the kind is
  * registry-driven:
  *
  *  - **`WallSystem`** — reads `dirtyNodes`, batches by level, runs
@@ -17,28 +16,16 @@ import { useEffect } from 'react'
  *  - **`WallCutout`** — cutaway-mode hide/show logic based on camera
  *    direction and `frontSide` / `backSide` interior/exterior tags.
  *
- * Both already live in `@pascal-app/viewer` and are wrapped in
- * `<LegacySystem kind="wall">` at the legacy mount point. When the
- * `wall` kind appears in `nodeRegistry`, those wrappers short-circuit and
- * this bundle takes over the mount via `RegisteredSystems`. The
- * components themselves are unchanged — no logic duplication during
- * Phase 3.
+ * Both live in `@pascal-app/viewer` and are wrapped in
+ * `<LegacySystem kind="wall">` at the legacy mount point. With wall
+ * registered, those wrappers short-circuit and this bundle takes over
+ * the mount via `RegisteredSystems`. The components themselves are
+ * unchanged — no logic duplication.
  *
  * Phase 6 deletes the legacy `<LegacySystem kind="wall">` wrappers; until
  * then this file is the single mount surface for wall's per-frame work.
  */
 const WallSystems = () => {
-  // Phase 3 verification log — confirms the registry took over the wall
-  // dispatch. Fires once when RegisteredSystems lazy-loads this bundle (so
-  // exactly once per viewer mount when NEXT_PUBLIC_USE_REGISTRY_FOR_WALL=true).
-  // Drop alongside the feature flag at Phase 3 sign-off.
-  useEffect(() => {
-    console.info('[wall:registry] system bundle mounted — registry path active')
-    return () => {
-      console.info('[wall:registry] system bundle unmounted')
-    }
-  }, [])
-
   return (
     <>
       <WallSystem />