Shadows land on the building, and the sky layers stop repeating themselves

**Shadows were the right size and pointed at nothing.** Last round fixed the
missing `updateProjectionMatrix()`, so the frustum finally became the size
every caller asks for — but nothing aimed it, and `sun.target` sits at the
world origin. A pack's origin is the **north-west corner of its slab**, so
for lumbridge-hq the box was off-centre by half the building: 14.4 m of a
48 m plate, about a third of the floor, fell outside the frustum and
neither cast nor received. Invisible while three's broken ±5 default made
shadows useless everywhere; obvious the moment they started working.

`SceneKitOptions` takes a `shadowTarget` now, both callers pass one, and
the light's target is added to the scene — which is the part that actually
matters, because `LightShadow.updateMatrices` reads `target.matrixWorld`
and an unparented `Object3D` is never reached by the traversal that
updates it. The sun is also placed relative to the target rather than the
origin, so light-to-target is exactly `sunDistance` for every direction,
which is the invariant each caller's `shadowNear`/`shadowFar` were chosen
against.

**`flights.ts` could not be tested, and that is why it was untested.** It
used a TypeScript parameter property — the one piece of TS syntax that
*emits code* rather than annotating a type — so Node's type stripping
refused the whole module. The bundler never cared, so nobody found out
until the first `node --test` file tried to import it. The module carrying
the worst bug this project has shipped was, by construction, the one
module that could not have a test. It has eleven now, including one that
fails if the live-aircraft repeat-skip is removed.

**Robots are on the plan panel** — a turned marker with a bow for heading,
in the one hue left that is neither the people-blue nor the camera-amber.

Review findings cleared across the four new sky/robot modules: a real
24 mm void at the ankle and an 8 mm hole through each forearm, a
per-frame allocation in the robot heading picker, a per-frame sort in the
starlink ranking, `uTime` growing unbounded until the cloud breath
quantises, and `DAY_REFERENCE`'s derivation which did not reproduce.

`createStarlinkMeshLayer` now takes a **board** radius — the same unit its
sibling takes — instead of a dome radius with nothing in the types to tell
them apart. That is the exact confusion that has already caused one real
bug here. `DOME_RADIUS_FACTOR` has one owner and is imported, not copied:
the points and the meshes must be on the same dome or a satellite that
grows geometry also jumps.

Several comments were wrong rather than merely stale — a fabricated claim
about `Object3D.clone`, a fabricated attribution to `Plan`, an inverted
`DoubleSide` argument, a triangle ledger citing a function that no longer
exists, and a defensive-call rationale that contradicted the paragraph
above it. In a codebase where the comments are the design record, those
are defects.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/engine/flights.ts

@@ -355,10 +355,27 @@ export class AdsbFlights implements FlightSource {
   private held: Aircraft[] = [];
   private heldAt = 0;
 
-  constructor(
-    private readonly endpoint: string,
-    private readonly region: SkyRegion,
-  ) {}
+  private readonly endpoint: string;
+  private readonly region: SkyRegion;
+
+  /**
+   * Fields assigned in the body rather than declared as parameter properties.
+   *
+   * That is not a style preference. A parameter property is the one piece of
+   * TypeScript syntax that *emits code* — it is a hidden assignment, not a type
+   * annotation — so Node's type stripping refuses the whole module with
+   * `ERR_UNSUPPORTED_TYPESCRIPT_SYNTAX`. The bundler never cared, so this went
+   * unnoticed until the first `node --test` file tried to import this layer and
+   * discovered it could not: the module with the worst bug this project has
+   * shipped was, by construction, the one module that could not be tested.
+   *
+   * The server has run under type stripping from the start and so has always
+   * been written this way; the browser engine simply never had to be.
+   */
+  constructor(endpoint: string, region: SkyRegion) {
+    this.endpoint = endpoint;
+    this.region = region;
+  }
 
   async poll(): Promise<Aircraft[]> {
     const { lat, lng } = this.region.center;