feat(ui): Fluid Studio Canvas, Creative Prompt Dock, Interactive Engine Cards, and Docked Copilot

[spelech]

Summary

This PR introduces a major UI overhaul that replaces the rigid numbered step boxes and disconnected drawers with a modern, high-density AI creation workstation.

Key Changes

• Fluid Studio Canvas & Creative Prompt Dock:
  • Center-stage responsive viewports for all 5 modalities: Image, Text, Video, 3D Mesh, and Audio.
  • Chat-style bottom prompt dock with multi-line autosizing textarea, quick preset chips, model badge, and parameter flyout (\⚙️ Settings).
• Interactive Engine Status Cards:
  • Modern status pill cards for Ollama, ComfyUI, SD Forge, and Kokoro TTS in the header and ribbon.
  • Live dot indicators (online/starting/offline), port numbers, and direct \▷ Start\ / \⏹ Stop\ controls.
• Docked Copilot & Knowledge Sidebar:
  • Integrated right-hand panel combining AI Assistant and Documentation with tab switching and search bridging.
  • Supports quick collapse and seamless pop-out into detached companion windows.
• Testing & Quality Assurance:
  • Expanded headless visual tree tests in \FluidStudioAndCopilotUiTests\ to verify all 5 modalities, parameter flyouts, and generation workflows end-to-end.
  • Codified deterministic testing guidelines in \docs/TESTING_GUIDELINES.md\ to eliminate test theater.
  • Updated all 10 documentation screenshots using Playwright automation.
  • Updated user guides and architecture specifications for v3.17.0.

Verification

• Automated Tests: 817 Passed, 0 Failed, 14 Skipped (live external endpoints).
• Code Quality:
  pm run lint\ (0 errors),
  px tsc --noEmit\ (0 errors).
• Build & Packaging: \pwsh scripts/fast_update.ps1 -NoLaunch\ passed cleanly.