## Summary
Add the G1.3 default visual baseline for `stage-tamagotchi-godot`.
This moves the Godot stage from a model-loading/runtime skeleton toward
a default presentation stage: fixed sky environment, visual grid ground,
centre marker, fixed lighting rig, camera ground constraint, and focused
material/rendering verification.
## Changes
- Add a fixed runtime visual preset for the Godot stage
- WorldEnvironment with the existing stage-ui-three HDRI skybox
- visual-only grid ground at world `Y=0`
- centre `T` marker at the world origin
- fixed directional light rig replacing the old single `OmniLight3D`
- Reuse the existing three-stage HDRI asset
- resolve
`packages/stage-ui-three/src/components/Environment/assets/sky_linekotsi_23_HDRI.hdr`
from a workspace checkout
- do not copy or move the asset into Godot `assets/`
- keep release packaging for the shared HDRI as a follow-up
- Add camera ground constraint in view-state rules
- clamp camera position `Y` during view-state normalisation / commit
- applies uniformly to local input, settings-driven patches, and future
remote/agent patches
- Patch vendored Godot MToon shader behaviour
- disable implicit WorldEnvironment ambient light for MToon materials
- use Godot alpha scissor / alpha-to-coverage path for cutout MToon
variants
- document the local vendor patch and removal conditions in
`docs/vendor-patches.md`
- Improve Godot rendering defaults
- enable 3D MSAA
- render 3D at 2x scale to avoid low-DPI/viewport scaling aliasing
- Add verification harnesses
- C# engine-local checks for camera ground constraint and HDRI asset
resolution
- Godot material rendering check scene for AvatarSample A/B material
import coverage
- Clean stage root presentation
- remove the old on-screen runtime status label
- keep Electron bridge and scene/view runtime wiring intact
## Notes
The HDRI path resolution is intentionally workspace-only in this PR.
Release packaging for sharing the three-stage HDRI with the exported
Godot sidecar remains a follow-up.
The MToon shader changes are deliberate vendor patches, recorded in
`docs/vendor-patches.md`, because `ambient_light_disabled`,
`alpha_to_coverage`, and alpha scissor behaviour are shader-level
changes rather than runtime material parameters.
The material rendering check validates imported material structure, not
visual golden output.
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Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
