Create Optimized Trains

## v1.3.0

### Focus

- Stability-first release focused on fixing regressions introduced after v1.2.0
- Restores smooth train behavior under real gameplay load (multiple trains, stations, chunk boundaries)
- Keeps most aggressive optimizations optional behind config flags

### Improvements

#### Movement and Physics Stability
- Added player proximity guards so nearby trains keep full physics/collision updates
- Aggressive throttling for other trains is now optional (`AGGRESSIVE_OTHER_TRAINS_THROTTLE`), default OFF
- Client-side `tickContraption()` throttling is blocked to avoid visual desync and “entry-state freeze”

#### Chunk Loading and Spawn Smoothness
- Startup grace period added to chunk filtering in `ChunkMapMixin` to avoid missing chunks on world join
- Chunk force-load pipeline now uses per-train rate limiting to reduce tick spikes when new trains appear
- Prioritizes immediate carriage chunks before lookahead/trailing chunks
- Added trailing buffer logic based on train length so rear carriages stay stable on long consists

#### LOD Consistency
- Fixed LOD classification bug where `lowDistance` was not being applied correctly
- Removed dynamic TPS-based shrinking of LOD distances (distance thresholds are now stable)
- Restored effective LOD behavior to v1.2.0 profile (no extra client-side shader LOD shift)
- Added fallback distance source (`positionAnchor`) when a carriage entity is not yet available

### Bug Fixes

#### Camera Shake While Sitting in Carriages
- Root cause addressed by preventing premature carriage entity creation in non-entity-ticking chunks
- Added priority chunk loading for carriages with player passengers to stabilize seat/camera sync

#### Trains Appearing as Distant LOD While Nearby
- Fixed client visual throttle path to never apply near the player/camera
- Nearby stationary trains no longer look choppy or “far LOD” when standing next to them

#### Visual and Flywheel Regressions
- `CarriageContraptionVisualMixin` begin-frame flow aligned with safer behavior (no incorrect skip path for moving trains)
- Removed problematic skip conditions that could freeze or under-update visuals

### Configuration

New/updated behavior in `create_optimized_trains-common.toml`:
- `AGGRESSIVE_OTHER_TRAINS_THROTTLE` (default: `false`)
- `GROUPING_ENABLED` default changed to `false` (experimental)
- `PROXY_ENABLED` default changed to `false` (experimental)
- `SHADER_BOOST_ENABLED` default changed to `false`
- `SHADER_LOD_SHIFT` default changed to `0`

### Notes

- Recommended migration from older configs: review existing `.toml` values, because existing files keep old values instead of new defaults
- This release is tuned for predictable behavior first; re-enable aggressive options only if needed per world/server

### Dependencies

- Minecraft 1.20.1
- Forge 47.4.16+
- Create Mod 6.0.8+
- Flywheel 1.0.5 (JiJ'd inside Create)
- Mixin 0.8.5