chore: migrate to TypeScript 6.0.2

- Upgrade typescript from 5.9.3 to 6.0.2
- Add explicit types: ['node'] to base tsconfig (TS6 breaking change)
- Remove deprecated baseUrl from server tsconfig
- All typecheck passing

bun.lock

@@ -7,7 +7,7 @@
       "devDependencies": {
         "@biomejs/biome": "^2.4.8",
         "turbo": "^2.8.20",
-        "typescript": "^5.9.3",
+        "typescript": "^6.0.0",
       },
     },
     "apps/desktop": {
@@ -1369,7 +1369,7 @@
 
     "type-fest": ["type-fest@5.5.0", "", { "dependencies": { "tagged-tag": "^1.0.0" } }, "sha512-PlBfpQwiUvGViBNX84Yxwjsdhd1TUlXr6zjX7eoirtCPIr08NAmxwa+fcYBTeRQxHo9YC9wwF3m9i700sHma8g=="],
 
-    "typescript": ["typescript@5.9.3", "", { "bin": { "tsc": "bin/tsc", "tsserver": "bin/tsserver" } }, "sha512-jl1vZzPDinLr9eUt3J/t7V6FgNEw9QjvBPdysz9KfQDD41fQrC2Y4vKQdiaUpFT4bXlb1RHhLpp8wtm6M5TgSw=="],
+    "typescript": ["typescript@6.0.2", "", { "bin": { "tsc": "bin/tsc", "tsserver": "bin/tsserver" } }, "sha512-bGdAIrZ0wiGDo5l8c++HWtbaNCWTS4UTv7RaTH/ThVIgjkveJt83m74bBHMJkuCbslY8ixgLBVZJIOiQlQTjfQ=="],
 
     "ufo": ["ufo@1.6.3", "", {}, "sha512-yDJTmhydvl5lJzBmy/hyOAA0d+aqCBuwl818haVdYCRrWV84o7YyeVm4QlVHStqNrrJSTb6jKuFAVqAFsr+K3Q=="],