feat: add @fresh/cli package for project management and code generation

[bartlomieju]

Summary

Introduces a new @fresh/cli package — a unified CLI tool installable globally as fresh:

deno install -gAf jsr:@fresh/cli

Commands

Command	Description
fresh init [dir]	Create a new project (delegates to @fresh/init)
fresh dev	Start dev server (auto-detects Vite vs Builder)
fresh build	Build for production
fresh start	Start production server
fresh generate <type> <name>	Generate files (aliases: gen, g)
fresh routes	List all routes with URL patterns and types

Generators

• route — page route with optional --handler flag
• api — API-only route (.ts, handler only)
• island — island component with props interface
• middleware — scoped or root middleware
• layout — scoped or root layout
• component — server component

Features

• Auto-detects Fresh project root (walks up to find deno.json with fresh import)
• Computes correct relative utils.ts import paths at any nesting depth
• Derives PascalCase component names from file paths (including dynamic params like [id])
• Route collision detection (e.g. about.tsx vs about/index.tsx)
• --dry-run to preview without writing
• --force to overwrite existing files
• Templates follow existing Fresh conventions (define.page, define.handlers, etc.)

Example usage

fresh generate route about
fresh generate route users/[id] --handler
fresh gen api health
fresh g island SearchBar
fresh generate middleware admin
fresh generate layout dashboard
fresh routes

Test plan

• 20 unit/integration tests covering all generators, utils, import path resolution, and collision detection
• Manual testing of dev, build, start commands against a real Fresh project
• Test global installation via deno install -gAf