render3d: a renderer that cannot draw says so and stops - LUDIC_HOME's leading ~ expanded (an unexpanded one left a run without shaders, logging 27 missing variants and drawing on), the SPIR-V manifest ends with E <count> and a cut or miscounted one is refused, and every such failure is a fault: r3d_open / r3d_load_step fail on it, r3d_fault() / r3d_fault_exit(code) for the game; tests/manifest_test

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/ludic.render3d/env.ludic

@@ -120,6 +120,8 @@ export state Render3dState {
   gpu_kind: int = 0                 # the backend running; 0 until gpu_select
   gpu_wanted: int = 0               # what was asked for (setting or R3D_GFX)
   gpu_fallback_reason: string = null # why the wanted backend is not the one running
+  r3d_fault: string = ""             # why the renderer cannot draw what it was asked to (gpu_fault.ludic)
+  gvk_missing: []string = null      # the programs asked for with no SPIR-V variant
   gpu_s_depth_test: int = -1
   gpu_s_depth_func: int = -1
   gpu_s_depth_write: int = -1