feat: enhance user input component with new styling and functionality

- Added informational styling to warning cards in user input component.
- Improved remaining days details and history display with new computed properties.
- Updated user input service to manage planning outcomes and traces more effectively.
- Enhanced leave planner service to classify remaining balances with detailed reasons.
- Expanded translation service to support new balance reasoning and suggestions.
- Updated translations for multiple languages to reflect new features and terminology.

CONTEXT.md

@@ -178,3 +178,6 @@ A valid deterministic plan produced after completing the planning objective orde
 
 **Remaining balance**:
 Any quantity left unspent by the optimization result, reported as unavoidable expiry, an unplaced at-risk balance, or a deferred balance.
+
+**Non-placement reason**:
+A concrete explanation of why a quantity of a leave balance remains unspent in the displayed plan, distinguishing a blocking condition from a decision to preserve leave for later. It includes the relevant dates, is distinct from the balance's expiry-based classification, and can be supported by recorded candidate evaluations.