feat(warp): add trace command for platform import debugging

[deyaaeldeen]

Summary

Add a new warp trace command that visualizes how #-prefixed imports resolve across different build targets. This helps catch bugs where a browser entry point accidentally imports a Node-only module, or vice versa.

Motivation

Recently we had a bug in the storage-common platform imports migration where indexPlatform-browser.mts was accidentally importing the Node version of StorageBrowserPolicyV2 instead of the browser version. This caused browser tests to fail because the cache-busting _ parameter wasn't being added to URLs.

This was difficult to debug because:

1. The import chain was several levels deep
2. The incorrect resolution wasn't obvious from looking at the source
3. The mismatch only showed up at runtime in specific tests

The Solution

The warp trace command walks the import graph from each exported entry point and shows how #-prefixed imports resolve under each target's conditions.

Example output:

╔══════════════════════════════════════════════════════════════╗
║  Platform Import Divergences                                 ║
╚══════════════════════════════════════════════════════════════╝

#platform/indexPlatform:
  browser      → src/indexPlatform-browser.mts
  esm          → src/indexPlatform.ts
  commonjs     → src/indexPlatform.ts

╔══════════════════════════════════════════════════════════════╗
║  Import Graphs by Target                                     ║
╚══════════════════════════════════════════════════════════════╝

Target: browser (browser)
Conditions: import, browser, default

└─ src/index.ts
   └─ #platform/indexPlatform → src/indexPlatform-browser.mts (browser)
      └─ #platform/policies/CachePolicy → src/policies/CachePolicy-browser.mts (browser)

The divergences section shows all #-prefixed imports that resolve differently across targets - this makes it immediately obvious which imports have platform-specific behavior.

The import graphs section shows the full resolution chain from each entry point, making it easy to trace how a specific module ends up being included.

CLI Options

warp trace [options]

Options:
  --depth <n>       Maximum import chain depth to trace (default: 10)
  --entry <subpath> Only trace specific entry points (repeatable)
  --json           Output machine-readable JSON for CI pipelines

Files Changed

• common/tools/warp/src/trace.ts - New module implementing the trace functionality
• common/tools/warp/src/cli.ts - Added trace command to CLI
• common/tools/warp/README.md - Documentation for the new command

[deyaaeldeen]

Added validation instead.