Transmission #048: PDD design and implementation plan for leveling

Closed the Prompt-Driven Development loop for skill/character leveling: detailed-design.md consolidates honed requirements with architecture, data models, error handling, tests, and diagrams; implementation/plan.md adds an eleven-step checklist from jittered skill thresholds through inventory Skills/Base tabs and end-to-end verification. summary.md indexes the planning folder under .agents/planning/2026-04-23-skill-character-levelling/.