fix(newos4): an invalid grep pattern returns a message, not an exception (v4.6.64)

Packet 8. `new RegExp(pattern)` sat unguarded in the terminal grep handler and in
VFS find()/grep(), so a bad pattern threw out of the command handler into the error
ledger -- the same ledger packet 2 had to stop trusting.

- module-fs.js grep: compile in try/catch, print
  "grep: invalid pattern: <pattern> (<engine message>)" as a warning and return
- virtual-fs.js find()/grep(): same guard, return [] and stash the message on
  _lastPatternError instead of throwing into the module error wrapper

Verified live on v4.6.64 with the packet's own repro: `grep "/\bug_id\" file` prints
the message, the error counter stays 0 (was: one ledger entry per call), a valid
pattern still matches, and fs.grep('[') returns [] instead of throwing.

0 files changed, 0 insertions, 0 deletions