fix(vite): count transforms without results in module timings - #599

Summary

A Vite transform hook can spend time on a module and return undefined or null. The inspector records that time, but the module summary excludes transforms that return no code. The hook's duration appears in plugin details but is missing from the module's transform and total times. This makes the module appear faster than it is.

This change includes every recorded transform when it adds up module timings. The tests cover undefined, null, unchanged code, changed code, and empty code. They also check the stored results and module sizes.

 module timing aggregation
-  include transforms with a code result
+  include all recorded transforms

Evidence

Results from the implementation checks:

• Before: The undefined and null cases reported 5ms instead of 1205ms and omitted the slow plugin. The three cases that returned code passed.
  After: All five cases passed.
• Tested the built package with actual Vite dev transform requests and a 1.2-second hook. All five return cases reported 1199–1201ms for that plugin, and each module total included that time.
• pnpm lint, pnpm test --run (356 passed, 2 skipped), pnpm typecheck, and pnpm build passed.

Merge Danger

Door: Two-way.

Blast Radius: Module-metrics.

Module timing totals and plugin entries now include hooks that ran without returning code.