[#51]

Improve NRQL query UX by adding shortcuts and time range flags.

Changes

1. Direct query shortcut: nrql "<query>" now works as a shortcut for nrql query "<query>"
2. Time range flags: Added --since and --until flags that inject SINCE/UNTIL clauses into the query
3. Better error messages: When no query is provided, shows helpful usage hints

Examples

# Before: only this worked
newrelic-cli nrql query "SELECT * FROM Transaction"

# Now: direct query also works
newrelic-cli nrql "SELECT * FROM Transaction"

# Time flags (appends to query)
newrelic-cli nrql "SELECT * FROM Log" --since "7 days ago"
newrelic-cli nrql "SELECT * FROM Log" --since "2025-01-01" --until "2025-01-15"

Error message improvement

$ newrelic-cli nrql
Error: query is required

Usage:
  newrelic-cli nrql "<query>"
  newrelic-cli nrql query "<query>"

Did you mean: newrelic-cli nrql query "<your-query>"?

Test Plan

• Build passes: make build
• Tests pass: make test
• Direct query works: ./newrelic-cli nrql "SELECT 1"
• Query subcommand still works: ./newrelic-cli nrql query "SELECT 1"
• --since flag works: ./newrelic-cli nrql "SELECT count(*) FROM Transaction" --since "1 hour ago"
• Error message is helpful: ./newrelic-cli nrql

Closes #51