Seed zones from CultMath's PCG hash and pin CultMath 0.2.3

Cut 8a seeded ZoneGenerator's Random from the float bits of CultMath's
hash(float2), the frac(sin) shader hash. On a 100x100 position grid that
gives 1625 distinct values, where Unity.Mathematics' uint hash separated
them. CultMath 0.2.3 adds the PCG integer hashes from Jarzynski and
Olano (JCGT 2020), so the seed now uses pcg3d(Position).x, the IEEE bits
of the float2 position with z held at 0, xored with the zone-name term
as before.

- Packages/manifest.json and packages-lock.json pin
  cultmath-unity-v0.2.3 (CultLib 0f2c1f04).
- Directory.Build.props sets CultLibRevision to the same commit.

This pin also brings in 0.2.2's normalize: a zero vector now gives NaN,
as dxc does and as Unity.Mathematics did before the swap. None of Cut
8a's normalize or LookRotation edits relied on a zero-safe normalize.
They are one-to-one type conversions, and 8a removed no guard. So no
guard is added.

Verified: headless Aetheria.Shared and AetherDb builds with 0 errors.
AetherDb census, factions and hardpoint-fit are byte-identical to the
captures. Unity 6000.3.24f1 batchmode compile gives 0 errors.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Packages/manifest.json

@@ -50,6 +50,6 @@
     "com.unity.modules.vr": "1.0.0",
     "com.unity.modules.wind": "1.0.0",
     "com.unity.modules.xr": "1.0.0",
-    "org.gamecult.cultmath": "https://github.com/GameCult/CultLib.git?path=/packages/cultmath/unity/org.gamecult.cultmath#cultmath-unity-v0.2.1"
+    "org.gamecult.cultmath": "https://github.com/GameCult/CultLib.git?path=/packages/cultmath/unity/org.gamecult.cultmath#cultmath-unity-v0.2.3"
   }
 }

Packages/packages-lock.json

@@ -243,11 +243,11 @@
       "url": "https://packages.unity.com"
     },
     "org.gamecult.cultmath": {
-      "version": "https://github.com/GameCult/CultLib.git?path=/packages/cultmath/unity/org.gamecult.cultmath#cultmath-unity-v0.2.1",
+      "version": "https://github.com/GameCult/CultLib.git?path=/packages/cultmath/unity/org.gamecult.cultmath#cultmath-unity-v0.2.3",
       "depth": 0,
       "source": "git",
       "dependencies": {},
-      "hash": "f0605367e0d7e57941a57bacb0b8cb8d893073be"
+      "hash": "0f2c1f04ef66a8b85c507747c508960ff1417ae0"
     },
     "com.unity.modules.accessibility": {
       "version": "1.0.0",