feat(ui-calculator): input validation, load caps, ceil display, modernization layout

- custom load capped at cargo capacity (error when exceeded); full load shows the cargo capacity; zero cargo pins load to empty and disables the toggle

- per-input red border + tooltip for every invalid value (blocks, techs, load, MAT, modernization target); no value may be negative; locking a speed is disabled when drive is zero

- display every computed number (results + goal-seek back-solved input) rounded up to 3 decimals via a shared pkg/calc Ceil3 bridged to wasm; engine keeps its own round-to-nearest util.Fixed*

- modernization total upgrade cost spans two columns (single line)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

ui/docs/calc-bridge.md

@@ -49,6 +49,7 @@ on the JS-side `globalThis.galaxyCore` (registered in
 | `shieldsForDefence` | `calc.ShieldsForDefence(targetDefence, sTech, restMass)` | `number\|null`  | calculator goal-seek (defence → shields) |
 | `cargoForEmptyMass` | `calc.CargoForEmptyMass(targetEmptyMass, restMass)`     | `number\|null`  | calculator goal-seek (mass → cargo)      |
 | `loadForFullMass`   | `calc.LoadForFullMass(targetFullMass, emptyMass, cTech)` | `number\|null`  | calculator goal-seek (loaded mass → load)|
+| `ceil3`             | `calc.Ceil3(value)` (`pkg/calc/number.go`)              | `number`        | calculator display rounding (round up to 3 dp) |
 
 `BombingPower` and the per-turn build loop are no longer engine-only:
 Phase 30 extracted `BombingPower` from