chore: update to ccstat v0.3.1 command syntax

fix: update parsers and fetch logic for new ccusage JSON format

refactor: migrate from npx ccusage to ccstat for improved performance

fix: update parsers and fetch logic for new ccusage JSON format

refactor: clean up obsolete code and verify performance

refactor: use cache helper in parser to eliminate duplicate code

feat: add cache retrieval helper function with stale fallback

refactor: update parser functions to use JSON validation utilities

feat: implement JSON validation utilities module

feat: create JSON validation utilities module

refactor: simplify fetch functions with centralized error handling

refactor: use date utilities module throughout codebase

fix: add fallback for EPOCHSECONDS in date utilities

feat: add date utilities module with caching

refactor: use centralized error handling in fetch functions