Refactoring round 7: split BehaviorSystem, fewer copies (#85)

Recurring cleanup round over the code since round 6 (056a622), 105
commits. Behaviour is unchanged. Duplicated code in src went from 29
clones with 229 lines (0.32 %) to 14 clones with 109 lines (0.15 %),
measured with jscpd and the same settings as round 6.

- BehaviorSystem.ts shrinks from 941 to 589 lines. Collecting the
  pulses (keys, timers, collisions, animations) moved to
  behaviorPulses.ts. The NodeContext the nodes receive moved to
  behaviorContext.ts. Imports from outside stay the same, TimeScaled
  is still exported from BehaviorSystem.ts.
- PointKindButton and drawPointGrip replace the "Point:" button with
  its menu and the point and handle drawing that the curve and the
  vector art tab each had on their own.
- lerpVec, cubicAt and splitCubic in src/core/util/vec.ts replace four
  copies of the cubic curve and two de Casteljau splits.
- mapNested in Properties.ts is the one walk over lists and structs
  that liveObjects and objectRefs did separately. withFieldRenamed
  and withoutField replace three copies of renaming a struct field
  and two of removing one.
- jsonBody and staleRevision build the JSON body and turn a 409 into
  StaleRevisionError for all stores. The auth store turns a 401 into
  its error in one place.
- Smaller helpers: structAssetFrom for the two "Make struct type"
  commands, shownObject in the inspector, selectedItem for the size
  gizmo and the polygon corners, solidTiles in the tilemap collision,
  requireVariablesAsset and requireBehaviorVariable.
- Left as is on purpose: the plain forwarding from the collision and
  physics systems to Solids, the pointer wiring of the canvases and
  the identical last lines of the two make commands.
- Removed unused code: tilemapTileIds and tilemapsUsing were never
  called since #128 and #131. EditorState.runtimeProject became unused
  with GameRun in #266. The assetId getter of the make commands was
  read only by a test.
- 60 values used only in their own file lost their export. The shader
  and particle node catalogues stay exported as in round 6.
- Five comments that told history now describe the current state. The
  doc comment of BehaviorSystem sits on the class again.
- README lists the struct, clip area and curve assets and mentions the
  game link from #266.

Findings:
- Deleting a tile that is painted on a tilemap leaves its cells in
  place, and they draw nothing. The delete dialog does not mention the
  tilemaps. That was probably the job of the unused tilemapsUsing.
  Left as is, because fixing it changes behaviour.
- The solid filter for tile surfaces was untested. A bent filter
  stayed green. A new test in tests/core/surface.test.ts now fails
  against it.

Tests:
- ./check.sh: 195 files, 2815 tests, exit 0 (one test removed with
  tilemapsUsing, one added for tile surfaces).
- Full e2e run: ALL PASSED, 1580 checks.
- Smokes jumprun, tetris, actor: 24, 19 and 21 checks, all passed.
  The example project files were restored byte for byte afterwards.
- Counter-checks, 12, all fail as expected: 10 in unit tests (among
  them mapNested, splitCubic, cubicAt, staleRevision, the stay pulse,
  the late timer and the time scale), 2 in the browser (Point button
  always enabled fails 47, selectedItem without a hit fails 29).

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

src/core/properties/PropertySchema.ts

@@ -280,7 +280,7 @@ export const SORT_WITH_PARENT_KEY = 'sortWithParent';
  * Whether a child is drawn in its parent's place instead of on its own (#232, see `drawSlots`).
  * A project stored before it reads as off, so it draws as it did; a new asset starts with it on.
  */
-export const SORT_PROPS: PropertySchema = [
+const SORT_PROPS: PropertySchema = [
   { key: SORT_WITH_PARENT_KEY, label: 'Sort with parent', kind: 'boolean', default: false, initial: true },
 ];
 
@@ -295,7 +295,7 @@ const CONTAINER_SORT_PROPS: PropertySchema = [
 /** A tilemap has no single place in the draw order, and the other types are not drawn at all. */
 const SORT_TYPES: ReadonlySet<AssetType> = new Set(['sprite', 'text', 'particles', 'container']);
 
-export function hasSortProps(type: AssetType): boolean {
+function hasSortProps(type: AssetType): boolean {
   return SORT_TYPES.has(type);
 }
 

src/core/properties/clip.ts

@@ -18,7 +18,7 @@ export interface ClipNode {
 }
 
 /** The area's own rectangle in world units. */
-export function clipCorners(props: PropertyBag, m: Mat): Vec2[] {
+function clipCorners(props: PropertyBag, m: Mat): Vec2[] {
   return footprintCorners('clip', props, m);
 }
 

src/core/properties/declaredRows.ts

@@ -4,9 +4,9 @@ import { flatDef, type FlatDef, type PropertyDef } from './PropertySchema';
 
 /** The params of a `Property` node in a shader or particle graph: its name and the row it declares. */
 export const PROPERTY_NAME_PARAM = 'name';
-export const PROPERTY_DEFAULT_PARAM = 'default';
-export const PROPERTY_MIN_PARAM = 'min';
-export const PROPERTY_MAX_PARAM = 'max';
+const PROPERTY_DEFAULT_PARAM = 'default';
+const PROPERTY_MIN_PARAM = 'min';
+const PROPERTY_MAX_PARAM = 'max';
 
 /** The params of a `Property` node, the same in both graphs but for the step of their number fields. */
 export function propertyNodeParams(step: number): PropertyDef[] {

src/core/properties/shaders.ts

@@ -31,7 +31,7 @@ export function propertyName(node: GraphNode): string {
  * rows the sprite brings itself: both rows would share the key and the uniform would read the
  * sprite's width instead of the declared default (#63). The compiler names which of the two it is.
  */
-export function isValidPropertyName(name: string): boolean {
+function isValidPropertyName(name: string): boolean {
   return isValidFieldName(name) && !isSpriteProp(name);
 }
 

src/core/properties/transform.ts

@@ -32,7 +32,7 @@ export interface LocalTransform {
   mirrorY: boolean;
 }
 
-export const NEUTRAL: LocalTransform = { rotation: 0, scale: 1, mirrorX: false, mirrorY: false };
+const NEUTRAL: LocalTransform = { rotation: 0, scale: 1, mirrorX: false, mirrorY: false };
 
 export function transformOf(props: PropertyBag): LocalTransform {
   return {