feat!: restructure CLI to ddog with domain-first commands and fix release workflow

[tmcinerney]

Summary

This PR restructures the CLI from dd-search to ddog with a domain-first command pattern and fixes the release-please workflow to properly trigger CI checks on automated PRs.

Breaking Changes

Command structure has changed to domain-first pattern. All commands now require both a domain and action verb:

• dd-search logs "<query>" → ddog logs search "<query>"
• dd-search spans "<query>" → ddog spans search "<query>"
• dd-search metrics "<query>" → ddog metrics query "<query>"
• dd-search list-metrics → ddog metrics list

Changes

Features

• CLI Restructuring: Migrated from flat command structure to domain-first organization
  • Commands grouped by domain (logs, spans, metrics)
  • Split monolithic cli.rs into modular structure (cli/{args,logs,metrics,shared,spans}.rs)
  • Reorganized commands directory to match domain structure
• Renamed Binary: Changed from dd-search to ddog throughout codebase

Bug Fixes

• Added missing logs module files that were ignored by global gitignore
• CI Workflow: Configured release-please to use RELEASE_PLEASE_TOKEN instead of GITHUB_TOKEN to properly trigger CI checks on automated release PRs

Documentation

• Updated README with new command syntax and examples
• Updated CHANGELOG with repository URL changes (dd-search → ddog)
• Updated all references in workflow files and pre-commit hooks

Impact

• 25 files changed: 340 additions, 246 deletions
• Major restructuring of CLI module architecture
• All command invocations require updating to new syntax
• Release artifacts renamed from dd-search-* to ddog-*

Testing

• All integration tests updated to use new command structure
• Pre-commit hooks (fmt, clippy) passing
• Maintains backward compatibility in query syntax and API interactions