feat: add account deletion feature (#85)

* feat: add account deletion feature

- Add DELETE /auth/me endpoint to delete user account and all data
- Add deleteAccount() method to AuthContext
- Add Delete Account button with confirmation modal in UserProfile
- Add danger zone styling (.btn-danger, .profile-danger-zone)
- Add i18n translations for EN and DE
- Add backend tests for account deletion endpoint
- Add timeout settings to frontend vitest.config.ts
- Reduce CI timeout for frontend tests (10min -> 5min)

* fix: improve delete account section layout

- Make profile modal scrollable with max-height
- Add proper horizontal margin to danger zone
- Align delete section with form content

* fix: use ConfirmModal component for delete account dialog

- Replace inline modal with existing ConfirmModal component
- Ensures consistent button styling across all modals
- Add UI consistency rule to AGENTS.md and copilot-instructions.md

* fix: consistent styling for delete account section

- Remove warning text (users know what delete means)
- Remove border-bottom from danger zone title (section has border-top)
- Update copilot-instructions and AGENTS.md with stricter UI consistency rules
- Remove unused deleteAccountHint i18n keys

* chore: remove pre-push test hook (CI handles tests)

Tests were running twice - in pre-push hook and GitHub CI.
Removing local pre-push tests since CI provides authoritative test results.
Use 'npm test' manually before pushing if you want local feedback.

frontend/src/components/Auth.tsx

@@ -1,5 +1,6 @@
 import { createContext, type ReactNode, useCallback, useContext, useEffect, useRef, useState } from "react";
 import { useTranslation } from "react-i18next";
+import { ConfirmModal } from "./ConfirmModal";
 
 // =============================================================================
 // Types (no roles - all users are equal)
@@ -32,6 +33,7 @@ interface AuthContextType {
 	updateProfile: (data: { currentPassword?: string; newPassword?: string }) => Promise<void>;
 	uploadAvatar: (file: File) => Promise<void>;
 	deleteAvatar: () => Promise<void>;
+	deleteAccount: () => Promise<void>;
 	authFetch: (input: RequestInfo | URL, init?: RequestInit) => Promise<Response>;
 }
 
@@ -254,6 +256,21 @@ export function AuthProvider({ children }: { children: ReactNode }) {
 		await refreshUser();
 	}
 
+	// Delete account
+	async function deleteAccount() {
+		const res = await fetch("/api/auth/me", {
+			method: "DELETE",
+			credentials: "include",
+		});
+
+		if (!res.ok) {
+			const err = await res.json().catch(() => ({ error: "Delete failed" }));
+			throw new Error(err.error || "Delete failed");
+		}
+
+		setUser(null);
+	}
+
 	// Fetch wrapper that automatically refreshes token on 401
 	const authFetch = useCallback(
 		async (input: RequestInfo | URL, init?: RequestInit): Promise<Response> => {
@@ -295,6 +312,7 @@ export function AuthProvider({ children }: { children: ReactNode }) {
 				updateProfile,
 				uploadAvatar,
 				deleteAvatar,
+				deleteAccount,
 				authFetch,
 			}}
 		>
@@ -551,7 +569,7 @@ export function RegisterForm({ onSuccess, onSwitchToLogin }: { onSuccess?: () =>
 // =============================================================================
 export function UserProfile({ onClose }: { onClose?: () => void }) {
 	const { t } = useTranslation();
-	const { user, updateProfile, uploadAvatar, deleteAvatar } = useAuth();
+	const { user, updateProfile, uploadAvatar, deleteAvatar, deleteAccount } = useAuth();
 	const [currentPassword, setCurrentPassword] = useState("");
 	const [newPassword, setNewPassword] = useState("");
 	const [confirmPassword, setConfirmPassword] = useState("");
@@ -559,6 +577,8 @@ export function UserProfile({ onClose }: { onClose?: () => void }) {
 	const [success, setSuccess] = useState("");
 	const [loading, setLoading] = useState(false);
 	const [avatarLoading, setAvatarLoading] = useState(false);
+	const [showDeleteConfirm, setShowDeleteConfirm] = useState(false);
+	const [deleteLoading, setDeleteLoading] = useState(false);
 	const fileInputRef = useRef<HTMLInputElement>(null);
 
 	// Close on Escape key
@@ -635,6 +655,18 @@ export function UserProfile({ onClose }: { onClose?: () => void }) {
 		}
 	}
 
+	async function handleDeleteAccount() {
+		setDeleteLoading(true);
+		setError("");
+		try {
+			await deleteAccount();
+			// User will be logged out automatically
+		} catch (err) {
+			setError(err instanceof Error ? err.message : "Delete failed");
+			setDeleteLoading(false);
+		}
+	}
+
 	if (!user) return null;
 
 	const hasChanges = currentPassword || newPassword || confirmPassword;
@@ -735,6 +767,38 @@ export function UserProfile({ onClose }: { onClose?: () => void }) {
 					</button>
 				</div>
 			</form>
+
+			{/* Delete Account Section */}
+			<div className="profile-section profile-danger-zone">
+				<h3 className="profile-section-title">{t("auth.deleteAccount", "Delete Account")}</h3>
+				<button type="button" className="btn btn-danger" onClick={() => setShowDeleteConfirm(true)}>
+					{t("auth.deleteAccount", "Delete Account")}
+				</button>
+			</div>
+
+			{/* Delete Confirmation Modal */}
+			{showDeleteConfirm && (
+				<ConfirmModal
+					title={t("auth.deleteAccountConfirmTitle", "Delete Account?")}
+					message={
+						<>
+							<p>
+								{t(
+									"auth.deleteAccountConfirmText",
+									"This will permanently delete your account and all your data (medications, settings, history). This action cannot be undone."
+								)}
+							</p>
+							{error && <div className="auth-error">{error}</div>}
+						</>
+					}
+					confirmLabel={t("auth.deleteAccountButton", "Yes, delete my account")}
+					cancelLabel={t("common.cancel", "Cancel")}
+					onConfirm={handleDeleteAccount}
+					onCancel={() => setShowDeleteConfirm(false)}
+					isLoading={deleteLoading}
+					confirmVariant="danger"
+				/>
+			)}
 		</div>
 	);
 }

frontend/src/components/SharedSchedule.tsx

@@ -274,8 +274,11 @@ export function SharedSchedule() {
 				for (let d = new Date(startDate); d <= end; d.setDate(d.getDate() + blister.every)) {
 					const t = d.getTime();
 					const isPast = d < todayStart;
-					// Generate dose ID matching Dashboard format: ${med.id}-${blisterIdx}-${whenMs}
-					const doseId = `${med.id}-${blisterIdx}-${t}`;
+					// Use date-only timestamp for stable ID (immune to time changes)
+					// This ensures changing intake times doesn't invalidate past dose tracking
+					// Must match buildSchedulePreview in schedule.ts exactly
+					const dateOnlyMs = new Date(d.getFullYear(), d.getMonth(), d.getDate()).getTime();
+					const doseId = `${med.id}-${blisterIdx}-${dateOnlyMs}`;
 					doses.push({
 						id: doseId,
 						when: t,

frontend/src/i18n/de.json

@@ -309,7 +309,11 @@
     "avatarUpdated": "Avatar aktualisiert",
     "avatarRemoved": "Avatar entfernt",
     "loginWithSSO": "Mit {{provider}} anmelden",
-    "or": "oder"
+    "or": "oder",
+    "deleteAccount": "Konto löschen",
+    "deleteAccountConfirmTitle": "Konto löschen?",
+    "deleteAccountConfirmText": "Dadurch werden dein Konto und alle deine Daten (Medikamente, Einstellungen, Verlauf) dauerhaft gelöscht. Diese Aktion kann nicht rückgängig gemacht werden.",
+    "deleteAccountButton": "Ja, mein Konto löschen"
   },
   "common": {
     "loading": "Wird geladen...",

frontend/src/i18n/en.json

@@ -311,7 +311,11 @@
     "avatarUpdated": "Avatar updated",
     "avatarRemoved": "Avatar removed",
     "loginWithSSO": "Login with {{provider}}",
-    "or": "or"
+    "or": "or",
+    "deleteAccount": "Delete Account",
+    "deleteAccountConfirmTitle": "Delete Account?",
+    "deleteAccountConfirmText": "This will permanently delete your account and all your data (medications, settings, history). This action cannot be undone.",
+    "deleteAccountButton": "Yes, delete my account"
   },
   "common": {
     "loading": "Loading...",

frontend/src/styles.css

@@ -4182,7 +4182,8 @@ h3 .reminder-icon.info-tooltip {
 .profile-modal {
 	max-width: 420px;
 	padding: 0;
-	overflow: hidden;
+	overflow-y: auto;
+	max-height: 90vh;
 }
 
 .profile-container {
@@ -4366,6 +4367,39 @@ h3 .reminder-icon.info-tooltip {
 	cursor: not-allowed;
 }
 
+/* Profile danger zone */
+.profile-danger-zone {
+	margin: 0 1.5rem 1.5rem;
+	padding-top: 1.5rem;
+	border-top: 1px solid var(--border-primary);
+}
+
+.profile-danger-zone .profile-section-title {
+	border-bottom: none;
+	padding-bottom: 0;
+	margin-bottom: 0.75rem;
+}
+
+.btn-danger {
+	background: #dc2626;
+	color: white;
+	border: none;
+	padding: 0.5rem 1rem;
+	border-radius: 6px;
+	font-weight: 500;
+	cursor: pointer;
+	transition: background 0.15s ease;
+}
+
+.btn-danger:hover:not(:disabled) {
+	background: #b91c1c;
+}
+
+.btn-danger:disabled {
+	opacity: 0.5;
+	cursor: not-allowed;
+}
+
 /* =============================================================================
    About Modal
    ============================================================================= */