feat: add shared overview and harden frontend session state (#407)

frontend/src/components/ShareDialog.tsx

@@ -4,6 +4,7 @@
  */
 
 import { Check, Copy, Link2, X } from "lucide-react";
+import { useEffect, useState } from "react";
 import { useTranslation } from "react-i18next";
 
 export interface ShareDialogProps {
@@ -40,8 +41,49 @@ export function ShareDialog({
 	onCopyShareLink,
 }: ShareDialogProps) {
 	const { t } = useTranslation();
+	const [overviewCopied, setOverviewCopied] = useState(false);
 	const closeLabel = t("common.close");
 	const copyLabel = shareCopied ? t("share.copied") : t("share.copyLink");
+	const overviewCopyLabel = overviewCopied ? t("share.copied") : t("share.copyOverviewLink");
+	const overviewLink = shareLink ? `${shareLink}/overview` : null;
+
+	useEffect(() => {
+		if (!shareLink) {
+			setOverviewCopied(false);
+		}
+	}, [shareLink]);
+
+	const copyOverviewLink = async () => {
+		if (!overviewLink) return;
+
+		const markCopied = () => {
+			setOverviewCopied(true);
+			setTimeout(() => setOverviewCopied(false), 2000);
+		};
+
+		if (navigator.clipboard?.writeText) {
+			try {
+				await navigator.clipboard.writeText(overviewLink);
+				markCopied();
+				return;
+			} catch {
+				// Fall back to textarea-based copy.
+			}
+		}
+
+		const textarea = document.createElement("textarea");
+		textarea.value = overviewLink;
+		textarea.style.position = "fixed";
+		textarea.style.opacity = "0";
+		document.body.appendChild(textarea);
+		textarea.select();
+		try {
+			document.execCommand("copy");
+			markCopied();
+		} finally {
+			document.body.removeChild(textarea);
+		}
+	};
 
 	// ESC is handled by the global handler in App.tsx to avoid double history.back()
 
@@ -91,6 +133,7 @@ export function ShareDialog({
 						return (
 							<div className="share-dialog-result">
 								<p className="share-success">{t("share.linkGenerated")}</p>
+								<p className="share-link-label">{t("share.scheduleLink")}</p>
 								<div className="share-link-box">
 									<input
 										type="text"
@@ -109,13 +152,34 @@ export function ShareDialog({
 										{shareCopied ? <Check size={18} aria-hidden="true" /> : <Copy size={18} aria-hidden="true" />}
 									</button>
 								</div>
+								<p className="share-link-label">{t("share.overviewLink")}</p>
+								<div className="share-link-box">
+									<input
+										type="text"
+										value={overviewLink ?? ""}
+										readOnly
+										className="share-link-input"
+										onClick={(e) => (e.target as HTMLInputElement).select()}
+									/>
+									<button
+										type="button"
+										className="btn-copy icon-only tooltip-trigger"
+										onClick={copyOverviewLink}
+										aria-label={overviewCopyLabel}
+										data-tooltip={overviewCopyLabel}
+									>
+										{overviewCopied ? <Check size={18} aria-hidden="true" /> : <Copy size={18} aria-hidden="true" />}
+									</button>
+								</div>
 								{shareCopied && <span className="share-copied-hint">{t("share.copied")}</span>}
+								{overviewCopied && <span className="share-copied-hint">{t("share.copied")}</span>}
 								<div className="share-dialog-footer">
 									<button
 										className="ghost"
 										onClick={() => {
 											onShareLinkChange(null);
 											onShareCopiedChange(false);
+											setOverviewCopied(false);
 										}}
 									>
 										{t("share.generateAnother")}
@@ -131,6 +195,7 @@ export function ShareDialog({
 								<label htmlFor="share-person-select">{t("share.selectPerson")}</label>
 								<select
 									id="share-person-select"
+									className="select-field"
 									value={shareSelectedPerson}
 									onChange={(e) => onShareSelectedPersonChange(e.target.value)}
 								>
@@ -146,6 +211,7 @@ export function ShareDialog({
 								<label htmlFor="share-period-select">{t("share.selectPeriod")}</label>
 								<select
 									id="share-period-select"
+									className="select-field"
 									value={shareSelectedDays}
 									onChange={(e) => onShareSelectedDaysChange(Number(e.target.value))}
 								>