--severity cannot select CRITICAL rules #11881

Semgrep 1.174.0 accepts rules with severity: CRITICAL and reports their
findings as CRITICAL, but the --severity command-line option rejects that
value. Explicitly selecting every documented severity also excludes the
critical rule.

Reproducer

Save this rule as CriticalRule.yml:

rules:
  - id: critical-test
    languages: [rust]
    severity: CRITICAL
    message: critical test finding
    pattern: dangerous()

Save this source as SeverityCriticalRepro.rs:

fn dangerous() {}

fn main() {
    dangerous();
}

Reproduction commands

semgrep scan --config CriticalRule.yml SeverityCriticalRepro.rs

semgrep scan --config CriticalRule.yml \
  --severity ERROR --severity WARNING --severity INFO \
  SeverityCriticalRepro.rs

semgrep scan --config CriticalRule.yml \
  --severity CRITICAL \
  SeverityCriticalRepro.rs

Actual result

The default command reports one finding with severity CRITICAL.

The command that explicitly selects INFO, WARNING, and ERROR reports no
finding. Passing --severity CRITICAL exits with status 2:

option '--severity': invalid value 'CRITICAL', expected one of
'INFO', 'WARNING' or 'ERROR'

The result was reproduced in three independent runs.

Expected result

Every severity that can be assigned to and reported for a rule should be
selectable with --severity. Explicitly selecting all supported severities
should preserve the default finding set.

Version

Semgrep 1.174.0