feat: add initial seed agent with chat UI

[devpavan04]

Note

This PR introduces the initial Seed agent implementation using Vercel AI SDK. The agent can generate p5.js sketches through conversation, but this is foundational work. The preview canvas, parameter controls UI, sketch persistence, and additional tools are not yet implemented. The system prompt and sketch creation contract (how the agent output integrates with the app) are still being explored.

CleanShot.2026-01-22.at.08.57.46.mp4

• chore: update package.json scripts
• chore: add husky pre-commit hook for lint and format checks
• chore: update layout and routes
• chore: update favicon
• chore: update empty state of new sketch and all sketches page
• chore: update default fonts - use Mona Sans and Jetbrains Mono
• chore: remove public folder
• chore: update styles and layout for sidebar and pages
• feat: add shimmer animation to New Sketch link in sidebar
• chore: add CLAUDE.md
• chore: add framer-motion library and refactor sidebar navigation items
• chore: add sidebar toggle tooltip to show keyboard shortcut
• chore: add zustand for state management
• chore: add split pane
• chore: update shadcn theme
• replace Tabs with UnderlineTabs in split-panel-layout and update CLAUDE.md with customization guidelines
• chore: refactor to colocation-first architecture and update CLAUDE.md
• chore: update left/right width and panel tab color
• chore: update font to Inter
• chore: update routes and remove shimmer animation
• chore: add ai-elements and expand shadcn component library
• fix: build
• chore: rename middleware.ts tp proxy.ts
• chore: configure initial seed agent with AI SDK