fix: CLI interval arg fallback for all endpoints + test suite

- Fixed interval positional arg on all 10 endpoints that take interval
  (was only fixed for 2 of them)
- Fixed index_history_price arg order in test script (registry order differs)
- Fixed false positive in test script (iv_error column matched 'error' regex)
- examples/test_all_endpoints.sh: tests all 61 endpoints with truncated output
- endpoint_test_results.md: live test results (42 pass, 18 skip, 1 no-data, 0 fail)

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

Author: userFRM