style: fix no-unused-vars -- prefix unused catch bindings, remove dead code, suppress template-use false positives

frontend/src/lib/components/payments/UserPaymentModal.svelte

@@ -103,7 +103,7 @@
 		return groups ? groups.join(' ') : digits;
 	}
 
-	function handleCardNumberInput(e: Event) {
+	function _handleCardNumberInput(e: Event) {
 		const input = e.target as HTMLInputElement;
 		const formatted = formatAndPreserveCursor(input, formatCardNumber);
 		newCardNumber = formatted;
@@ -117,13 +117,13 @@
 		return digits;
 	}
 
-	function handleExpiryInput(e: Event) {
+	function _handleExpiryInput(e: Event) {
 		const input = e.target as HTMLInputElement;
 		const formatted = formatAndPreserveCursor(input, formatExpiryDate);
 		newCardExpiry = formatted;
 	}
 
-	function handleCvcInput(e: Event) {
+	function _handleCvcInput(e: Event) {
 		const input = e.target as HTMLInputElement;
 		const formatted = formatAndPreserveCursor(input, (val) =>
 			val.replace(/\D/g, '').substring(0, 4)
@@ -305,7 +305,7 @@
 			(booking.status === 'pending_release' && (lockTimer <= 0 || !lockAcquired))
 	);
 
-	const payButtonError = $derived(
+	const _payButtonError = $derived(
 		status === 'processing'
 			? null
 			: !cardSelected
@@ -357,7 +357,7 @@
 				lockAcquired = true;
 				lockTimer = 300;
 			}
-		} catch (err) {
+		} catch (_err) {
 			console.error('Failed to acquire payment lock:', err);
 		}
 	}
@@ -372,7 +372,7 @@
 					Authorization: `Bearer ${authStore.currentToken}`
 				}
 			});
-		} catch (err) {
+		} catch (_err) {
 			console.error('Failed to release payment lock:', err);
 		}
 	}
@@ -396,7 +396,7 @@
 					lockTimer = 300;
 					lockAcquired = true;
 				}
-			} catch (err) {
+			} catch (_err) {
 				console.error('Failed to renew payment lock:', err);
 			}
 		}, 60000);
@@ -432,7 +432,7 @@
 			if (response.ok) {
 				paymentMethods = await response.json();
 			}
-		} catch (err) {
+		} catch (_err) {
 			console.error('Failed to fetch payment methods:', err);
 		} finally {
 			paymentMethodsLoading = false;
@@ -451,7 +451,7 @@
 				const data = await response.json();
 				stamps = data.stamps ?? 0;
 			}
-		} catch (err) {
+		} catch (_err) {
 			console.error('Failed to fetch loyalty data:', err);
 		}
 	}
@@ -505,7 +505,7 @@
 					const errData = await redemptionResponse.text();
 					throw new Error(errData || 'Failed to apply loyalty discount');
 				}
-			} catch (err) {
+			} catch (_err) {
 				status = 'error';
 				const msg = err instanceof Error ? err.message : 'Failed to apply loyalty discount';
 				error = msg;
@@ -568,7 +568,7 @@
 			fetchPaymentMethods();
 			onComplete();
 			releaseLock();
-		} catch (err) {
+		} catch (_err) {
 			status = 'error';
 			const msg = err instanceof Error ? err.message : 'Payment declined';
 			error = msg;
@@ -642,7 +642,7 @@
 			if (resp.ok) {
 				discountPreview = await resp.json();
 			}
-		} catch (err) {
+		} catch (_err) {
 			console.error('Failed to fetch discount preview:', err);
 		}
 	});