Merge main (gene system G1-G5, phases C-D) into the multiplayer branch

Main independently adopted the engine Core/Host split in G1, so the
scene adaptations conflicted with identical changes here — resolved in
main's favor (its scenes also carry the gene-driven world). Kept from
this branch: BootScene's --connect path into MultiplayerScene, the
buildAtlases switch in GameContent.Load (with the Task.Run lambda fix
its optional parameter requires), net.* localization keys, and the
Net/Server/Web projects in the solution. Program.cs now has both CLI
modes: --check-content (main) and --connect (here). The engine pointer
lands on d044caf, which linearly contains both lines of work.

Verified on the merged tree: 366 engine tests pass, --check-content
reports genes/traits intact, and a live --listen server replicates
moving pawns to the probe.

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

Mods/Core/Languages/en/ui.json

@@ -67,6 +67,10 @@
   "plant.stage.sprout": "sprout",
   "plant.stage.sapling": "sapling",
   "plant.stage.mature": "mature",
+  "product.wood": "wood",
+  "product.grass": "grass",
+  "product.berry": "berries",
+  "product.acorn": "acorn",
   "pawn.being": "being",
   "pawn.bear": "bear",
   "pawn.deer": "deer",

Mods/Core/Languages/ru/ui.json

@@ -67,6 +67,10 @@
   "plant.stage.sprout": "всходы",
   "plant.stage.sapling": "саженец",
   "plant.stage.mature": "взрослое",
+  "product.wood": "древесина",
+  "product.grass": "трава",
+  "product.berry": "ягоды",
+  "product.acorn": "жёлудь",
   "pawn.being": "житель",
   "pawn.bear": "медведь",
   "pawn.deer": "олень",