feat(cli): add --file flag for file review and refactor prompt generation

- Inject current date into review prompts to improve LLM context accuracy
- Remove unused `module` field from package.json

package.json

@@ -1,6 +1,5 @@
 {
   "name": "lmc",
-  "module": "src/index.ts",
   "type": "module",
   "private": true,
   "bin": {