docs: add intro context and task name display note

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: branchseer

docs/stdio.md

@@ -1,6 +1,6 @@
 # Task Standard I/O
 
-How stdin, stdout, and stderr are connected to task processes, controlled by the `--log` flag.
+How stdin, stdout, and stderr are connected to task processes, controlled by the `--log` flag. Largely inspired by [npm-run-all2](https://github.com/bcomnes/npm-run-all2)'s stdio handling, with differences explained in the [appendix](#appendix-npm-run-all2-behavior).
 
 ## The `--log` Flag
 
@@ -16,6 +16,8 @@ vp run build --log=<mode>
 
 ### Examples
 
+In `interleaved` mode, task names are omitted from the command line to keep output clean. In `labeled` and `grouped` modes, the `[pkg#task]` prefix is necessary to identify which task produced each line.
+
 #### `interleaved`
 
 Output goes to the terminal as soon as it's produced. When running multiple tasks in parallel, lines from different tasks may intermix: