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.

src/app/services/leave-planner.core.ts

@@ -5044,7 +5044,53 @@ function qualityMetrics(
 	};
 }
 
-function remainingBalances(state: State, context: SearchContext): RemainingBalance[] {
+function nonPlacementReason(
+	balance: NormalizedBalance,
+	state: State,
+	context: SearchContext,
+	completed: boolean,
+): PlanningReason {
+	if (balance.expiryDate < context.horizon.start)
+		return reason('unavoidable-expiry', 'This balance expired before the planning horizon.');
+	if (balance.availableFrom >= context.horizon.end)
+		return reason(
+			'available-after-horizon',
+			'This balance becomes available after the last planning date.',
+		);
+	const dates = context.workingDays.filter(
+		(date) => date >= balance.availableFrom && date <= balance.expiryDate,
+	);
+	if (!dates.length)
+		return reason(
+			'no-working-date',
+			'There is no working date within both the horizon and this balance’s validity period.',
+		);
+	if (dates.every((date) => context.declaredDates.has(date) || state.placements.has(date)))
+		return reason(
+			'all-dates-occupied',
+			'Every working date within this balance’s validity period is already occupied in the displayed plan.',
+		);
+	if (!completed)
+		return reason(
+			'calculation-incomplete',
+			'The calculation stopped before completing its planning priorities.',
+		);
+	if (balance.expiryDate > context.horizon.end)
+		return reason(
+			'preserved',
+			'This balance expires after the horizon; the planner retained no additional placement under its planning priorities.',
+		);
+	return reason(
+		'not-established',
+		'The calculation did not establish a precise reason for leaving this balance unspent.',
+	);
+}
+
+function remainingBalances(
+	state: State,
+	context: SearchContext,
+	completed: boolean,
+): RemainingBalance[] {
 	return state.balances
 		.filter((balance) => balance.remaining > 0)
 		.map((balance) => {
@@ -5054,8 +5100,6 @@ function remainingBalances(state: State, context: SearchContext): RemainingBalan
 					: compareDate(balance.expiryDate, context.horizon.end) <= 0
 						? 'at-risk'
 						: 'deferred';
-			const code =
-				classification === 'unavoidable-expiry' ? 'unavoidable-expiry' : classification;
 			return {
 				id: balance.id,
 				type: balance.type,
@@ -5063,14 +5107,7 @@ function remainingBalances(state: State, context: SearchContext): RemainingBalan
 				availableFrom: balance.availableFrom,
 				expiryDate: balance.expiryDate,
 				classification,
-				reason: reason(
-					code,
-					classification === 'unavoidable-expiry'
-						? 'This balance expired before the planning horizon.'
-						: classification === 'at-risk'
-							? 'This balance expires within the planning horizon.'
-							: 'This balance remains available after the planning horizon.',
-				),
+				reason: nonPlacementReason(balance, state, context, completed),
 				earned: balance.earned,
 				sourceRuleId: balance.sourceRuleId,
 			};
@@ -5442,7 +5479,7 @@ function makePlan(
 			ruleIds: [...placement.ruleIds].sort(),
 			supporting: placement.supporting,
 		}));
-	const remaining = remainingBalances(state, context);
+	const remaining = remainingBalances(state, context, stages.includes('dates'));
 	const windowContributions = timeWindowContributions(state, context);
 	const patternContributions = ifThenContributions(state, context);
 	const plan: PlanOutcome = {