Each mission type now has a typeConfig (moneyFactor, xpFactor, repFactor,
riskShift, requiredItemChance, lootChance). startMission checks minLevel.
claimMission awards loot items on success; applies a police-scaled fine
on failure. New abandonMission endpoint (POST /:id/abandon, −1 rep).
computeSuccessChance extracted for reuse between listAvailable and claim.
Narrative template pool expanded (4 templates × 4 types).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>