fix: Windows ESM import errors in sunpeak CLI

[udaykakade25]

About Issue

Node's ESM loader rejects Windows absolute paths like 'C:...' because it parses the drive letter as a URL scheme. Convert paths to file:// URLs before passing them to dynamic import() and child_process.spawn().

• bin/sunpeak.js: wrap command imports with pathToFileURL().href so 'sunpeak dev', 'inspect', 'build', etc. load on Windows.
• bin/commands/dev.mjs: replace 'new URL(import.meta.url).pathname' with 'fileURLToPath(import.meta.url)' to avoid the doubled drive letter ('C:\C:...') that broke the build watcher and the --prod-resources initial build.

BEFORE

 $ pnpm --filter sunpeak dev                                                                 
                                                                                              
  > sunpeak@0.20.12 dev D:\work\sunpeak\packages\sunpeak                                      
  > pnpm -C template dev                                                                      
                                                                                              
                                                                                              
  > sunpeak-app@0.1.0 dev D:\work\sunpeak\packages\sunpeak\template                           
  > sunpeak dev                                                                               
                                                                                              
  Error: Only URLs with a scheme in: file, data, and node are supported by the default ESM    
  loader. On Windows, absolute paths must be valid file:// URLs. Received protocol 'd:'       
   ELIFECYCLE  Command failed with exit code 1.                                               
  D:\work\sunpeak\packages\sunpeak:                                                           
   ERR_PNPM_RECURSIVE_RUN_FIRST_FAIL  sunpeak@0.20.12 dev: pnpm -C template dev             
  Exit status 1

AFTER FIX

$ pnpm --filter sunpeak dev  

> sunpeak@0.20.15 dev C:\Users\jayka\OneDrive\Desktop\sunpeak\packages\sunpeak
> pnpm -C template dev


> sunpeak-app@0.1.0 dev C:\Users\jayka\OneDrive\Desktop\sunpeak\packages\sunpeak\template
> sunpeak dev

Starting dev server...

Starting MCP server with 7 simulation(s) (Vite HMR)...
Sunpeak MCP server listening on http://localhost:8000
  MCP endpoint: http://localhost:8000/mcp
  Vite HMR: enabled (source files served with hot reload)
[build] Building resources for the MCP server for non-ChatGPT hosts...
[build] Watching src/resources/ for changes...
Connecting to MCP server: http://localhost:8000/mcp
[MCP] ← initialize
[MCP] Registered 7 tool(s) (6 UI, 1 plain), 4 resource(s)
[MCP] Session started: daa286e4... (local, 1 active)
[MCP] ← notifications/initialized (daa286e4...)
Connected. Discovering tools and resources...
[MCP] ← tools/list (daa286e4...)
[MCP] ← resources/list (daa286e4...)
Found 7 tool(s), 6 resource(s).
10:34:40 pm [vite] (client) Re-optimizing dependencies because vite config has changed
  ➜  Local:   http://localhost:3000/
  ➜  Network: http://10.239.70.135:3000/
  ➜  press h + enter to show help