Adds approvals.deny to config.yaml — a list of fnmatch globs matched
against terminal commands. A match blocks unconditionally, BEFORE the
--yolo / /yolo / approvals.mode=off bypass, making it the user-editable
counterpart to the code-shipped hardline blocklist.
- Checked in both command gates (check_dangerous_command and
check_all_command_guards), after the hardline floor and sudo-stdin
guard, before the yolo bypass and permanent allowlist.
- Matching runs over the same normalized/deobfuscated command variants
as the dangerous-pattern detector, case-insensitive.
- Opt-in: empty/absent list is a no-op; behavior unchanged.
Supersedes the trust-engine approach from #21500 with a minimal
config-native design: the only capability the existing stack lacked
was deny-that-beats-yolo. Allow already exists (command_allowlist),
ask already exists (session approvals).
