feat: garden calendar + lists integrations (task 74)

- calendar-bridge.ts and lists-bridge.ts isolate cross-module deps
- scheduleOnCalendar action: creates event from care schedule with 30-min
  slot, title convention (Water/Fertilize/Repot/Prune/custom), reminder opt
- pushOverdueToTaskList action: inserts one task per overdue (plant+schedule)
  pair into the default task list, skips duplicate text entries
- CareScheduleEditor: per-row calendar 📅 button opens inline form with
  calendar select + optional reminder minutes + success link to /calendar
- Garden page header: PushOverdueButton with auto-dismissing feedback toast

src/modules/garden/server/actions.ts

@@ -1,6 +1,6 @@
 "use server";
 
-import { and, eq } from "drizzle-orm";
+import { and, eq, lte, sql } from "drizzle-orm";
 import { revalidatePath } from "next/cache";
 import { z } from "zod";
 import { db } from "@/lib/db";
@@ -8,7 +8,9 @@ import { getCurrentSession } from "@/lib/session";
 import { logActivity } from "@/modules/_core/activity";
 import { cancelReminder, scheduleReminder } from "@/modules/_core/reminders";
 import { gardenCareLogs, gardenCareSchedules, gardenContainers, gardenPlants } from "../schema";
+import { createCalendarEvent } from "./calendar-bridge";
 import { updateScheduleAfterCare } from "./care-schedule";
+import { addListItem, getList, listLists } from "./lists-bridge";
 
 const containerInput = z.object({
   name: z.string().trim().min(1).max(120),
@@ -481,3 +483,114 @@ export async function toggleCareSchedule(input: { id: string; enabled: boolean }
 
   revalidatePath(`/garden/plants/${row.plantId}`);
 }
+
+// ─── Calendar integration ─────────────────────────────────────────────────────
+
+function buildCareTitle(careType: string, plantName: string): string {
+  const verbs: Record<string, string> = {
+    watering: "Water",
+    fertilizing: "Fertilize",
+    repotting: "Repot",
+    pruning: "Prune",
+  };
+  const verb = verbs[careType];
+  return verb ? `${verb} ${plantName}` : `${careType} — ${plantName}`;
+}
+
+const scheduleOnCalendarInput = z.object({
+  scheduleId: z.string().uuid(),
+  calendarId: z.string().uuid(),
+  reminderMinutesBefore: z.number().int().min(0).max(1440).optional(),
+});
+
+export async function scheduleOnCalendar(input: z.input<typeof scheduleOnCalendarInput>) {
+  const parsed = scheduleOnCalendarInput.parse(input);
+  const { household } = await getCurrentSession();
+
+  const [row] = await db
+    .select({
+      nextDueAt: gardenCareSchedules.nextDueAt,
+      careType: gardenCareSchedules.careType,
+      plantName: gardenPlants.name,
+    })
+    .from(gardenCareSchedules)
+    .innerJoin(gardenPlants, eq(gardenCareSchedules.plantId, gardenPlants.id))
+    .where(
+      and(
+        eq(gardenCareSchedules.id, parsed.scheduleId),
+        eq(gardenCareSchedules.householdId, household.id),
+      ),
+    )
+    .limit(1);
+
+  if (!row) throw new Error("Forbidden");
+  if (!row.nextDueAt) throw new Error("This schedule has no upcoming due date set.");
+
+  const startAt = row.nextDueAt;
+  const endAt = new Date(startAt.getTime() + 30 * 60 * 1000);
+  const title = buildCareTitle(row.careType, row.plantName);
+
+  await createCalendarEvent({
+    calendarId: parsed.calendarId,
+    title,
+    startAt,
+    endAt,
+    allDay: false,
+    notes: `Scheduled from garden. Next due: ${startAt.toLocaleDateString()}`,
+    remindMinutesBefore: parsed.reminderMinutesBefore ?? null,
+  });
+
+  revalidatePath("/calendar");
+}
+
+// ─── Lists integration ────────────────────────────────────────────────────────
+
+export async function pushOverdueToTaskList(): Promise<{ added: number }> {
+  const { household } = await getCurrentSession();
+
+  const overduePairs = await db
+    .select({
+      plantName: gardenPlants.name,
+      careType: gardenCareSchedules.careType,
+      nextDueAt: gardenCareSchedules.nextDueAt,
+    })
+    .from(gardenCareSchedules)
+    .innerJoin(gardenPlants, eq(gardenCareSchedules.plantId, gardenPlants.id))
+    .where(
+      and(
+        eq(gardenCareSchedules.householdId, household.id),
+        eq(gardenCareSchedules.enabled, true),
+        lte(gardenCareSchedules.nextDueAt, sql`now()`),
+      ),
+    );
+
+  if (overduePairs.length === 0) return { added: 0 };
+
+  const taskLists = await listLists({ type: "task" });
+  const taskList = taskLists[0];
+  if (!taskList) return { added: 0 };
+
+  const listDetail = await getList(taskList.id);
+  const existingTexts = new Set(listDetail.items.map((i) => i.text));
+
+  let added = 0;
+  for (const pair of overduePairs) {
+    const title = buildCareTitle(pair.careType, pair.plantName);
+    if (existingTexts.has(title)) continue;
+
+    const daysOverdue = pair.nextDueAt
+      ? Math.abs(Math.floor((Date.now() - pair.nextDueAt.getTime()) / (1000 * 60 * 60 * 24)))
+      : 0;
+
+    await addListItem({
+      listId: taskList.id,
+      text: title,
+      notes: `Overdue by ${daysOverdue} day(s)`,
+      dueAt: pair.nextDueAt,
+    });
+    existingTexts.add(title);
+    added++;
+  }
+
+  return { added };
+}