refactor: decentralize turbo task config — move compile/dist to workspace turbo.json

Sink package-specific tasks from root turbo.json into workspace configs:
- compile/compile:* → apps/server/turbo.json (only server compiles binaries)
- dist/dist:* → apps/desktop/turbo.json (only desktop distributes)
- Cross-package deps (desktop→server#compile) owned by desktop config
- Desktop dist scripts no longer bypass Turbo by calling bun run build

Root turbo.json reduced from 16 to 4 generic lifecycle tasks.

apps/desktop/turbo.json

@@ -4,6 +4,22 @@
   "tasks": {
     "build": {
       "outputs": ["out/**"]
+    },
+    "dist": {
+      "dependsOn": ["build", "@furtherverse/server#compile"],
+      "outputs": ["dist/**"]
+    },
+    "dist:linux": {
+      "dependsOn": ["build", "@furtherverse/server#compile:linux"],
+      "outputs": ["dist/**"]
+    },
+    "dist:mac": {
+      "dependsOn": ["build", "@furtherverse/server#compile:mac"],
+      "outputs": ["dist/**"]
+    },
+    "dist:win": {
+      "dependsOn": ["build", "@furtherverse/server#compile:win"],
+      "outputs": ["dist/**"]
     }
   }
 }