[BUG] examples/hooks/bash_command_validator_example.py: regex bugs cause silent false negatives on common shapes

What's Wrong?

The bash validator hook example silently fails to flag two common command shapes that the rules were intended to catch:

1. grep as the source of a pipeline (e.g. grep foo | wc -l) is exempted by the negative lookahead (?!.*\|), even though grep is the leading command and rg foo is the better substitute. The lookahead was apparently intended to exempt grep-as-downstream-filter (e.g. cat foo | grep bar), but the ^grep\b anchor already handles that case correctly — the lookahead does no useful work and produces a false negative.

1. find invocations with predicates before -name (e.g. find / -type f -name '*.log') are missed because the regex ^find\s+\S+\s+-name\b only accepts find PATH -name. This shape is arguably the most common real-world form of find -name.

What Should Happen?

Both shapes should match their respective rules. Empirical case matrix (run against examples/hooks/bash_command_validator_example.py at HEAD):

| Command | Current | Should be |
|---|---|---|
| grep foo \| wc -l | not flagged | flagged |
| grep foo bar.txt \| head -5 | not flagged | flagged |
| find / -type f -name '*.log' | not flagged | flagged |
| find . -type d -name node_modules | not flagged | flagged |
| find . -maxdepth 2 -name '*.md' | not flagged | flagged |

Steps to Reproduce

1. Open examples/hooks/bash_command_validator_example.py at HEAD of anthropics/claude-code.
2. Copy _VALIDATION_RULES into a Python REPL.
3. Run:

``python
import re
re.search(r"^grep\b(?!.*\|)", "grep foo | wc -l") # returns None — bug
re.search(r"^find\s+\S+\s+-name\b", "find / -type f -name '*.log'") # returns None — bug
``

Claude Code Version

N/A — bug is in examples/hooks/bash_command_validator_example.py at HEAD of anthropics/claude-code, observable by reading the file.

Platform / OS / Terminal

N/A — file-level bug in a checked-in example.

Is this a regression?

No, this never worked.

Additional Information

Fix is two regex tweaks (drop the broken lookahead, allow predicates between find and -name). Happy to send a PR if you'd like — let me know if there's a preferred scope (e.g. fix-only vs. fix-plus-test-file). Considered switching to shlex-based parsing to also catch prefix forms (sudo grep, time grep, etc.) but that would substantially expand the example's scope; can do as a follow-up if desired.