Hibryda
a89e2b9f69
docs: restructure docs — eliminate v3- prefix, merge findings, create decisions.md
Merge v3-task_plan.md content into architecture.md (data model, layout system,
keyboard shortcuts) and new decisions.md (22-entry categorized decisions log).
Merge v3-findings.md into unified findings.md (16 sections covering all research).
Move progress logs to progress/ subdirectory (v2.md, v3.md, v2-archive.md).
Rename v3-release-notes.md to release-notes.md. Update all cross-references.
Delete v3-task_plan.md and v3-findings.md (content fully incorporated).