feat(desktop): 固化样例世界与昼光呈现

[变更性质]
- this commit adds a deterministic desktop bootstrap for the playable sample world.

[新增功能]
- this commit places the avatar away from the home doorway and separates villagers from scene footprints.
- this commit provides a warm high-contrast daylight tint and exits autoplay after SampleComplete.

[实现方案]
- this commit isolates desktop spawn policy in WorldBootstrap and routes game startup and sample tests through it.
- this commit adds regression coverage for spawn positions, spacing, determinism, and daylight tint.

[影响范围]
- this commit affects the Desktop application and Desktop tests only.
- this commit preserves Kernel behavior and does not include unrelated worktree changes.

0 files changed, 0 insertions, 0 deletions