Use explicit .ts extensions for Node-compatible imports

Node's --experimental-strip-types requires explicit .ts extensions on
relative imports. Add allowImportingTsExtensions to both app tsconfigs
and update server-side imports in planner and journal for consistency.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/journal/tsconfig.json

@@ -9,6 +9,7 @@
   "compilerOptions": {
     "rootDirs": [".", "./.react-router/types"],
     "noEmit": true,
+    "allowImportingTsExtensions": true,
     "types": ["vite/client"],
     "paths": {
       "~/*": ["./app/*"]