Allow medications with only a generic name (no commercial name required) (#311)

* Initial plan

* feat: allow generic name only for medications (frontend changes)

- Add getMedDisplayName() helper for consistent name display
- Update validation to require either commercial or generic name
- Update all display locations to use display name fallback
- Add i18n keys for nameOrGenericRequired in en.json and de.json
- Remove required attribute from commercial name field
- Update FIELD_LIMITS.name.min from 1 to 0

Co-authored-by: DanielVolz <3275994+DanielVolz@users.noreply.github.com>

* feat: allow generic name only for medications (backend changes)

- Update Zod schema to allow empty name with cross-field refinement
- Update reminder scheduler to use name || genericName for display
- Update planner routes to match medications by display name
- Update existing tests to match new validation behavior

Co-authored-by: DanielVolz <3275994+DanielVolz@users.noreply.github.com>

* fix: update placeholder text and fix FIELD_LIMITS test

- Remove "(optional)" from generic name placeholder in en/de
- Update types.test.ts to expect FIELD_LIMITS.name.min = 0

Co-authored-by: DanielVolz <3275994+DanielVolz@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: DanielVolz <3275994+DanielVolz@users.noreply.github.com>

backend/src/services/intake-reminder-scheduler.ts

@@ -106,8 +106,9 @@ async function autoMarkDueIntakesAsTaken(
 		}
 
 		const medicationTakenBy = parseTakenByJson(med.takenByJson);
+		const medDisplayName = med.name || med.genericName || "";
 		const todaysIntakes = getTodaysIntakes(
-			med.name,
+			medDisplayName,
 			intakes,
 			medicationTakenBy,
 			med.pillWeightMg,
@@ -415,9 +416,10 @@ async function checkAndSendIntakeRemindersForUser(
 		);
 		// Medication-level takenBy (for fallback/display purposes)
 		const medicationTakenBy = parseTakenByJson(med.takenByJson);
+		const medDisplayName = med.name || med.genericName || "";
 
 		logger.debug(
-			`[IntakeReminder] User ${settings.userId}: Processing medication "${med.name}" with ${intakes.length} intakes`
+			`[IntakeReminder] User ${settings.userId}: Processing medication "${medDisplayName}" with ${intakes.length} intakes`
 		);
 
 		// Filter intakes that have reminders enabled (per-intake setting or medication-level)
@@ -438,7 +440,7 @@ async function checkAndSendIntakeRemindersForUser(
 
 			// Always get upcoming intakes (15 min before) for first reminders
 			const upcomingIntakes = getUpcomingIntakes(
-				med.name,
+				medDisplayName,
 				[intake],
 				REMINDER_MINUTES_BEFORE,
 				medicationTakenBy,
@@ -465,7 +467,7 @@ async function checkAndSendIntakeRemindersForUser(
 			// If repeat reminders enabled, also check for missed intakes (past the intake time)
 			if (settings.repeatRemindersEnabled) {
 				const allTodaysIntakes = getTodaysIntakes(
-					med.name,
+					medDisplayName,
 					[intake],
 					medicationTakenBy,
 					med.pillWeightMg,