feat: A-frame tent + portal walk-through field + texture polish

- camping: replace cube tent with A-frame slope panels (tent_panel_l/r) +
  cardinal_direction permutations; vote-skip sleep that mixes
  player.isSleeping bed sleepers with tent occupants and respects the
  playersSleepingPercentage gamerule; new weathered-canvas texture.
- lobby: walk-through silverlabs:portal_field block (no collision,
  translucent swirl, cross-plane geo) auto-placed above each portal frame;
  invisible silverlabs:portal_label entity floats above each portal with
  the destination world name; transfer detection now scans down through
  the field to find the destination frame.
- postal: regenerate post_office and mailbox block textures so they fill
  the full block face (brick + POST plaque, full red panel with slot/latch
  /flag/rivets) instead of small sprites floating on transparent.
- dynamite + tow-boat: ship the addons (volumes wired into all four
  worlds; enabled_packs registers them into Mya's world).
- art: build-textures.py extended; build-art-catalog.py added to project.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tow-boat-addon/tow_boat_RP/animations/tow_boat.animation.json

@@ -0,0 +1,27 @@
+{
+  "format_version": "1.8.0",
+  "animations": {
+    "animation.tow_boat.bob": {
+      "loop": true,
+      "animation_length": 4.0,
+      "bones": {
+        "root": {
+          "position": {
+            "0.0": [0, 0, 0],
+            "1.0": [0, 0.6, 0],
+            "2.0": [0, 0, 0],
+            "3.0": [0, -0.4, 0],
+            "4.0": [0, 0, 0]
+          },
+          "rotation": {
+            "0.0": [0, 0, 0],
+            "1.0": [1.5, 0, -0.5],
+            "2.0": [0, 0, 0],
+            "3.0": [-1.0, 0, 0.5],
+            "4.0": [0, 0, 0]
+          }
+        }
+      }
+    }
+  }
+}