refactor: address code review feedback on logs stats/summary commands

[Copilot]

Addresses 9 code review comments from PR #118 focusing on code duplication, type safety, and edge case handling in the new awf logs stats and awf logs summary commands.

Changes

Type consolidation

• Moved duplicate StatsFormat/SummaryFormat type definitions to shared LogStatsFormat in types.ts
• Both command-specific types now alias the shared type

Reduced duplication

• Extracted format validation logic into validateFormat() helper (eliminates 3 identical validation blocks)
• Refactored 50+ lines of duplicated command handler logic into logs-command-helpers.ts with:
  • discoverAndSelectSource() - handles log source discovery and selection with conditional logging
  • loadLogsWithErrorHandling() - wraps aggregation with error handling

Type safety improvements

• Added runtime validation for source.path and source.containerName before use (replaces non-null assertions)
• Throws clear error messages when required fields missing

Edge case fixes

• Guard against -Infinity in formatStatsPretty() when all domains filtered out
• Fix domain count discrepancy in markdown format by showing "(X valid)" when "-" domain present

Code quality

• Simplified chalk fallback using Proxy pattern instead of 6-property object literal
• Documented intentional logging behavior difference between stats (logs for non-JSON) and summary (logs only for pretty)

// Before: duplicate validation in 3 places
if (!validFormats.includes(options.format)) {
  logger.error(`Invalid format: ${options.format}. Must be one of: ${validFormats.join(', ')}`);
  process.exit(1);
}

// After: single helper
validateFormat(options.format, validFormats);

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[github-actions]

📰 BREAKING: Smoke Copilot is now investigating this pull request. Sources say the story is developing...

[github-actions]

💥 WHOOSH! Smoke Claude springs into action on this pull request! [Panel 1 begins...]

[github-actions]

Smoke Test: Copilot Engine - PASS

GitHub MCP: ✅

• docs: streamline README for first-time visitors #111: docs: streamline README for first-time visitors
• feat: add install script with sha256 validation #108: feat: add install script with sha256 validation

File Writing: ✅
Bash Tool: ✅

📰 BREAKING: Report filed by Smoke Copilot fer issue #126 🗺️

[github-actions]

Smoke Test Results - Claude Engine

Last 2 Merged PRs:

• [WIP] Add tests for blocked domain detection in log parsers #119: [WIP] Add tests for blocked domain detection in log parsers
• docs: streamline README for first-time visitors #111: docs: streamline README for first-time visitors

Test Results:

• ✅ GitHub MCP: Fetched recent PRs successfully
• ✅ File Writing: Created /tmp/gh-aw/agent/smoke-test-claude-20378122408.txt
• ✅ Bash Tool: Verified file contents
• ✅ Playwright MCP: Navigated to GitHub (title: "GitHub · Change is constant. GitHub keeps you ahead. · GitHub")

Status: PASS

💥 [THE END] — Illustrated by Smoke Claude fer issue #126 🗺️