Implement safe messaging content filter

Build a module that scans user-submitted text for crisis language and surfaces appropriate resources — without ever blocking the user's ability to post.

scanContent(text: string): SafetyCheckResult

// SafetyCheckResult: {
//   flagged: boolean,
//   severity: 'low' | 'medium' | 'high',
//   matchedPatterns: string[],
//   suggestedResources: Resource[]
// }
// Resource: { name: string, contact: string, url: string, available24h: boolean }

Requirements:

1. Match against a curated keyword/phrase list for self-harm and crisis language using word-boundary regex (\b). The list should be maintainable (exported constant), not buried in logic.
2. Severity levels: 'low' = general distress language, 'medium' = explicit self-harm references, 'high' = immediate crisis indicators
3. Always include these resources for 'medium' and 'high': Crisis Text Line (HOME to 741741), 988 Suicide & Crisis Lifeline, NAMI Helpline (1-800-950-NAMI)
4. Never modify, censor, or block the original text
5. Case-insensitive matching

Write tests for: high-severity match, low-severity match, false positive guard ("shoot, I forgot", "I'm dying laughing"), clean content returning flagged: false.