feat(design): enhanced reschedule conflict detection with lockup & redemption (#443)

[laurentketterle-hub]

Description

Enhanced the payout reschedule modal's conflict analysis with lockup period, redemption window, and clustering detection (#443).

Changes

• Lockup period conflicts (hard): detects when payout falls within active lockup
• Redemption window conflicts (hard): detects when payout coincides with redemption date
• Near lockup boundary (soft): warns when within 3 days of lockup ending
• Payout clustering (info): flags when 3+ payouts share the same date
• Redemption proximity (info): warns when within 5 days of redemption window
• Actionable suggestions: every conflict now includes a resolution suggestion
• Added LockupPeriod and RedemptionWindow types

Testing

• 8 test cases covering all new conflict types
• Tests verify conflict severity, messages, and suggestions
• Boundary case: no conflicts when all clear

Backward Compatible

• lockupPeriods and redemptionWindows are optional params (default to [])
• Existing callers continue to work unchanged

Closes #443

[laurentketterle-hub]

I claim this bounty. PR ready for review.