feat(pattern-toolkit): adopt Pattern Lab tool into suite with 300 DPI PNG export

[iocfinc]

Summary\n- Adds a new "Pattern Toolkit" route (/pattern-toolkit) porting the Pattern Lab Cells → Modules generator into our shared EditorShell.\n- Seeded RNG + edit mode + config copy/apply + SVG/PNG(300 DPI via pHYs)/JPG export.\n\nDetails\n- Core: cyrb128→sfc32, quarterPath geometry, pure SVG builder.\n- UI: GTK-styled controls (layout/colors/interact/shape/process/output), selection overlay, keyboard shortcuts.\n- Export: new ensurePngDPI helper in export-engine to embed 300 DPI pHYs for PNG.\n- Registry: adds a fourth live toolkit to the launcher.\n- Tests: core determinism/geometry + launcher update.\n\nAcceptance\n- Deterministic re-render from seed and modules, config round-trips including orientations.\n- PNG exports report 300 DPI in design tools.\n- Keyboard: R/Shift+R, ArrowLeft/Right, Esc.\n\nQA\n- Lint, tests, and build are green locally.\n- Visual QA: Chrome DevTools MCP not available in this run; will attach screenshots in a follow-up if requested.\n\nHandover\n- Based on: /Users/iraoliverfernando/Documents/Playground/pattern-lab/HANDOVER-GengarToolkit.md

[github-actions]

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