Monthly variance analysis: budget vs actual with bridges

Perform monthly variance analysis for {period}.

Inputs:
- Actuals P&L: {actuals}
- Budget/forecast P&L: {budget}
- Volume metrics (units, users, hours): {volume_metrics}
- FX rates (if relevant): {fx_rates}
- Known events: {known_events}
- Thresholds: {abs_threshold} and {pct_threshold}

Output:
1) Variance table by line item with flags.
2) Bridge analysis for key lines (revenue, COGS, labor, marketing).
3) Narrative explanations for flagged items (2–4 sentences each).
4) Follow-up questions and owner assignments.

Keep it concise and numbers-first.