Docs: hygiene sweep — stale/misattributed doc-comments + CLAUDE.md example

- Repoint CLAUDE.md testing example from the deleted HeartbeatSystemTests to HealthApplyDamageSystemTests.
- Stale deleted-system refs: ResourceFieldSpawner/ClutterFieldSpawner(+Authoring) now cite RoomFieldSystem (was ExpeditionFieldSystem); BuildPlaceRequest drops the deleted RegionTransitRequest from its 'mirrors' list.
- Stale package version: 'Netcode 1.13.2' -> 'Netcode 1.x' in ProjectileClassificationSystem + BuildPlaceRequest.
- WorldCollisionComponents: remove the duplicated EnvironmentMask summary line; FeelConfig: fix the mangled 'is hitmap)' sentence.

Comment/doc only; compiles clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Assets/_Project/Scripts/Simulation/Building/BuildPlaceRequest.cs

@@ -4,10 +4,10 @@ namespace ProjectM.Simulation
 {
     /// <summary>
     /// Client -&gt; server request to build a structure of <see cref="StructureType"/> at grid cell
-    /// (<see cref="CellX"/>, <see cref="CellZ"/>). A one-off action, so an RPC (mirrors StorageOpRequest /
-    /// RegionTransitRequest). StructureType is a byte; the cell is two int scalars (NOT an int2) to stay
+    /// (<see cref="CellX"/>, <see cref="CellZ"/>). A one-off action, so an RPC (mirrors StorageOpRequest).
+    /// StructureType is a byte; the cell is two int scalars (NOT an int2) to stay
     /// within the project's scalar-only RPC payload precedent (avoids first-of-its-kind composite-math-in-RPC
-    /// codegen risk on Netcode 1.13.2). The server re-validates legality + cost authoritatively.
+    /// codegen risk on Netcode 1.x). The server re-validates legality + cost authoritatively.
     /// </summary>
     public struct BuildPlaceRequest : IRpcCommand
     {