feat(cloud): add cost-report API support (Beta)

[joshrotenberg]

Summary

Add support for the new Redis Cloud cost-report API endpoints announced at https://redis.io/docs/latest/operate/rc/api/examples/generate-cost-report/

Changes

Library (redis-cloud)

• Add cost_report module with CostReportHandler
• Add CostReportCreateRequest with builder pattern for ergonomic request construction
• Add CostReportFormat (csv/json), SubscriptionType (pro/essentials), and Tag types
• Add get_bytes() method to CloudClient for downloading binary content

CLI (redisctl)

• Add cloud cost-report generate command with comprehensive filtering options:
  • --start-date / --end-date (YYYY-MM-DD format, max 40 days range)
  • --format (csv or json, defaults to csv)
  • --subscription (filter by subscription IDs, repeatable)
  • --database (filter by database IDs, repeatable)
  • --subscription-type (pro or essentials)
  • --region (filter by regions, repeatable)
  • --tag (filter by key:value tags, repeatable)
  • Async operation support (--wait, --wait-timeout)
• Add cloud cost-report download command with --output option

Tests

• Add CLI help tests for cost-report commands

API Endpoints

• POST /cost-report - Generate cost reports in FOCUS format
• GET /cost-report/{costReportId} - Download generated reports

Usage Examples

# Generate a cost report for January 2025
redisctl cloud cost-report generate --start-date 2025-01-01 --end-date 2025-01-31

# Generate with filters and wait for completion
redisctl cloud cost-report generate --start-date 2025-01-01 --end-date 2025-01-31 \
  --subscription 123 --region us-east-1 --tag team:marketing --wait

# Download the report
redisctl cloud cost-report download cost-report-12345-abcdef --output report.csv

Notes

• The cost report API is currently in Beta
• Reports are in FOCUS (FinOps Cost and Usage Specification) format
• Maximum date range is 40 days

Closes #478