feat: Add Designer Feedback Loop and Tooling (M11.6)

[Copilot]

Designer-facing CLI tool and workflows for balance iteration without requiring code changes. Enables non-engineers to run sweeps, compare configs, test tuning overlays, and view reports.

Changes

New CLI Tool: echoes-balance-studio

• sweep - Run parameter sweeps with sensible defaults
• compare - Side-by-side config comparison
• test-tuning - Apply YAML overlays for quick validation
• history / view - Browse historical balance reports
• report - Generate enhanced HTML dashboards with filtering/sorting
• overlays - List and validate config overlays

Config Overlay System

• deep_merge() merges overlay YAML into base config without modifying originals
• Overlays stored in content/config/overlays/
• Pattern mirrors existing difficulty presets

Documentation

• docs/gengine/designer_balance_guide.md - Diagnosis workflows, iteration guides, case study (Industrial Tier faction balancing)

Usage

# Run exploratory sweep
uv run echoes-balance-studio sweep --strategies balanced aggressive --ticks 50

# Test tuning change with overlay
uv run echoes-balance-studio test-tuning --overlay content/config/overlays/example_tuning.yml

# Generate filtered HTML report
uv run echoes-balance-studio report --database build/sweep_results.db --filter-strategy balanced

Tests

28 tests covering CLI commands, overlay merging, and report generation.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>11.6.1 — Designer Feedback Loop and Tooling (M11.6)</issue_title>
<issue_description>## Description
Build designer-facing tools and workflows that make balance iteration accessible to non-engineers. Provide intuitive interfaces for running sweeps, viewing reports, and experimenting with tuning changes without requiring code changes.

Acceptance Criteria

• Command-line tool echoes-balance-studio provides guided workflows for designers
• Workflows include: "Run exploratory sweep", "Compare two configs", "Test tuning change", "View historical reports"
• Configuration changes testable via YAML overlays (similar to difficulty presets) without modifying base configs
• Interactive report viewer (HTML dashboard or Jupyter notebook) allows filtering, sorting, and drilling into results
• Designer-focused documentation: "How to diagnose dominant strategies", "Iterating on action costs", "Testing narrative pacing changes"
• Example workflows demonstrated with case studies (e.g., "Balancing the Industrial Tier faction")
• At least 8 tests covering CLI commands, config overlay loading, and report generation

Priority

Low (Optional enhancement - UX improvement)

Dependencies

• ✅ 11.1.1 (Batch Parameter Sweeps) - Completed
• ✅ 11.3.1 (Analysis and Balance Reporting) - Completed

Responsible

gamedev-agent (with designer/PM feedback loop)

References

See .pm/tracker.md task 11.6.1 for complete details and context.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes 11.6.1 — Designer Feedback Loop and Tooling (M11.6) #70

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

[SorraTheOrc]

Closed as duplicate of #73