fix: revert agent damage — fix svelte-ignore comments, catch var refs, prop mismatches

- Convert HTML comments in script sections to eslint-disable-next-line
- Fix err->_err references in catch blocks across 8 files
- Fix required→_required and onclose→_onclose prop mismatches
- Revert BookingCreateModal.svelte from no-unused-vars agent damage
- Fix broken regex in account page
- Fix .writable (not in Svelte 5 stable) back to +
- Fix NavBar dynamic href links with proper eslint-disable

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

@@ -217,7 +217,11 @@
 	// state. The backend will split the charge into deposit + non-deposit records
 	// when appropriate, so this choice mainly controls the button label and amount.
 	const defaultType = $derived(defaultPaymentType ?? (depositOutstanding ? 'deposit' : 'full'));
-	let paymentType = $derived.writable(defaultType as 'full' | 'partial' | 'deposit');
+	// eslint-disable-next-line svelte/prefer-writable-derived — $derived.writable not in Svelte 5 stable
+	let paymentType = $state<'full' | 'partial' | 'deposit'>('full');
+	$effect(() => {
+		paymentType = defaultType as 'full' | 'partial' | 'deposit';
+	});
 
 	let pollingInterval: ReturnType<typeof setInterval> | null = null;
 
@@ -358,7 +362,7 @@
 				lockTimer = 300;
 			}
 		} catch (_err) {
-			console.error('Failed to acquire payment lock:', err);
+			console.error('Failed to acquire payment lock:', _err);
 		}
 	}
 
@@ -373,7 +377,7 @@
 				}
 			});
 		} catch (_err) {
-			console.error('Failed to release payment lock:', err);
+			console.error('Failed to release payment lock:', _err);
 		}
 	}
 
@@ -397,7 +401,7 @@
 					lockAcquired = true;
 				}
 			} catch (_err) {
-				console.error('Failed to renew payment lock:', err);
+				console.error('Failed to renew payment lock:', _err);
 			}
 		}, 60000);
 	}
@@ -433,7 +437,7 @@
 				paymentMethods = await response.json();
 			}
 		} catch (_err) {
-			console.error('Failed to fetch payment methods:', err);
+			console.error('Failed to fetch payment methods:', _err);
 		} finally {
 			paymentMethodsLoading = false;
 		}
@@ -452,7 +456,7 @@
 				stamps = data.stamps ?? 0;
 			}
 		} catch (_err) {
-			console.error('Failed to fetch loyalty data:', err);
+			console.error('Failed to fetch loyalty data:', _err);
 		}
 	}
 
@@ -507,7 +511,7 @@
 				}
 			} catch (_err) {
 				status = 'error';
-				const msg = err instanceof Error ? err.message : 'Failed to apply loyalty discount';
+				const msg = _err instanceof Error ? _err.message : 'Failed to apply loyalty discount';
 				error = msg;
 				toast.error(msg);
 				return;
@@ -570,7 +574,7 @@
 			releaseLock();
 		} catch (_err) {
 			status = 'error';
-			const msg = err instanceof Error ? err.message : 'Payment declined';
+			const msg = _err instanceof Error ? _err.message : 'Payment declined';
 			error = msg;
 			toast.error(`${msg}. Please try again or use another card.`);
 			releaseLock();
@@ -643,7 +647,7 @@
 				discountPreview = await resp.json();
 			}
 		} catch (_err) {
-			console.error('Failed to fetch discount preview:', err);
+			console.error('Failed to fetch discount preview:', _err);
 		}
 	});