Add markdown export and consolidate output format flags

[Copilot]

Adds markdown export capability with emoji indicators (✅ better, ❌ worse, ➖ same) and consolidates output format selection into a unified -o/--output flag.

Changes

• New functions:

  • _verdict_to_emoji(): Maps verdict strings to emoji
  • render_comparison_markdown(): Renders comparison tables in markdown format
  • print_section_markdown(): Outputs hierarchical markdown headers (##, ###, ####)

• CLI: Consolidated --json and --markdown into -o/--output {text,json,markdown} flag

  • text (default): Human-readable table format
  • json: Machine-readable JSON format
  • markdown: Markdown tables with emoji indicators

• API: Refactored compare_reports() to use single output_format parameter instead of separate as_json and as_markdown flags

• Backward compatibility note: This is a breaking change for CLI users. The old --json and --markdown flags are replaced by -o json and -o markdown respectively.

Examples

# Default text output
$ python3 compare_runs.py base/ current/

# JSON output
$ python3 compare_runs.py base/ current/ -o json

# Markdown output with emojis
$ python3 compare_runs.py base/ current/ -o markdown

Markdown Output Sample

Aggregated

Metric	Base	Current	Diff	% Change	Verdict
Requests/s	286.200	300	+13.800	+4.8%	✅
Failure Count	7	4	-3	-42.9%	✅
Average Response Time	85.200	78.500	-6.700	-7.9%	✅

Useful for GitHub PR comments, issue tracking, or documentation where color codes don't render.

Original prompt

Add the ability to export results as markdown. Instead of colors use emoji for showing better worse or same

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[dev-ankit]

@copilot consolidate and use --output or -o with markdown and json as options instead of separate arge

[Copilot]

@copilot consolidate and use --output or -o with markdown and json as options instead of separate arge

Done! Consolidated into -o/--output flag with choices: text (default), json, or markdown.

Examples:

python3 compare_runs.py base/ current/              # text (default)
python3 compare_runs.py base/ current/ -o json      # JSON output
python3 compare_runs.py base/ current/ -o markdown  # Markdown with emojis

Help output:

-o {text,json,markdown}, --output {text,json,markdown}
                      Output format: text (default), json, or markdown with emoji 
                      indicators (✅ better, ❌ worse, ➖ same)

All 161 tests updated and passing. Changes in commit d9bfc49.