Merge the review fixes, and take Junie's on the hit radius with them

Carries the shared reference-viewport module and the cached card lookup up from
the branch they were reviewed on, and answers the one comment left against this
one.

The orthographic branch of the star field's hit test multiplied the angular size
by the frustum's half-height and then divided the result by that same
half-height. The two cancel: `setProjection` had already sized the sprite as
`angular * halfHeight / tan(REFERENCE_FOV/2)`, so dividing back out by the
half-height leaves the reference field of view and nothing else. Both
projections are one formula over a different angle now — which is also one
fewer division by a number that is zero if the frustum ever degenerates.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016jxMkwA2rbicdGxHosecYi

src/app/features/galaxy-system/host-star-rings.ts

@@ -2,14 +2,11 @@ import * as THREE from 'three/webgpu';
 import { color, float, instancedBufferAttribute, mix, modelViewMatrix, smoothstep, uniform, uv, vec2, vec4 } from 'three/tsl';
 
 import { StarRecord } from '../../shared/models/star.model';
+import { PIXELS_TO_ANGULAR_SIZE, REFERENCE_FOV_DEGREES } from './angular-size';
 
 /** Ring diameter in screen pixels at the reference viewport — angular, like the star points. */
 const RING_SIZE_PX = 12;
 const RING_PEAK_OPACITY = 0.35;
-/** Same reference as `StarFieldRenderer`, so a ring and its star agree on what a pixel is. */
-const REFERENCE_VIEWPORT_HEIGHT_PX = 900;
-const REFERENCE_FOV_DEGREES = 55;
-const PIXELS_TO_ANGULAR_SIZE = (2 * Math.tan((REFERENCE_FOV_DEGREES * Math.PI) / 180 / 2)) / REFERENCE_VIEWPORT_HEIGHT_PX;
 /** Ring radius and stroke half-width in quad-uv units (the quad runs 0..1, centre 0.5). */
 const RING_RADIUS_UV = 0.42;
 const RING_STROKE_UV = 0.06;