[log] Add debug logging to 5 pkg/ files for better troubleshooting visibility

[github-actions]

Summary

• pkg/workflow/template_injection_utils.go: Added logging to extractRunBlocks (reports extracted run block count), removeHeredocContent (logs input/output sizes), and replaceOutsideQuotedHeredocs (logs quoted region count and replacement values)
• pkg/parser/schedule_cron_detection.go: Added logging to IsWeeklyCron (positive match with minute/hour/dow) and IsCronExpression (both valid-expression and invalid-field-character cases)
• pkg/agentdrain/miner.go: Added logging to match (candidate count, best similarity, match result) and TrainEvent (entry with stage info)
• pkg/agentdrain/anomaly.go: Added logging to NewAnomalyDetector (creation with threshold values)
• pkg/parser/frontmatter_hash.go: Added logging to computeFrontmatterHashFromContent (file path, content size, inlined-imports strategy), extractRelevantTemplateExpressions (input size, found expression count), and processImportsTextBased (import count, cycle detection skips, result count)

Test plan

• make build passes with no compilation errors
• make test-unit passes with all tests green
• All log arguments are side-effect free (only reading existing variables)
• No test files (*_test.go) were modified
• Maximum 5 files changed
• Each file uses its existing package-level logger (no new logger declarations needed)

🤖 Generated with [Claude Code]((claude.com/redacted)

Generated by Go Logger Enhancement · ● 1.3M · ◷

• expires on May 1, 2026, 9:47 PM UTC