feat: garden care reminder bodies, task sync, upload cleanup

- care reminders now fire with plant-specific body ("Time to water Pothos")
  via title/body columns on the reminders table (migration 0016)
- bi-directional task sync: checking off a garden-linked task list item
  creates a care log; logging care from garden marks the linked task done
  (list_items.metadata stores gardenPlantId + gardenCareType linkage)
- upload error response no longer leaks debug detail; error message
  corrected from "5 MB" to "100 MB"

src/app/api/uploads/route.ts

@@ -37,7 +37,7 @@ export async function POST(request: Request) {
   }
 
   if (file.size > MAX_FILE_SIZE) {
-    return NextResponse.json({ error: "File exceeds 5 MB limit" }, { status: 413 });
+    return NextResponse.json({ error: "File exceeds 100 MB limit" }, { status: 413 });
   }
 
   const rawExt = file.name.split(".").pop() ?? "bin";
@@ -54,15 +54,8 @@ export async function POST(request: Request) {
       "Content-Type": file.type,
     });
   } catch (err) {
-    const msg = err instanceof Error ? err.message : String(err);
     console.error("Upload failed", err);
-    return NextResponse.json(
-      {
-        error: "Upload service unavailable",
-        detail: process.env.NODE_ENV !== "production" ? msg : undefined,
-      },
-      { status: 503 },
-    );
+    return NextResponse.json({ error: "Upload service unavailable" }, { status: 503 });
   }
 
   return NextResponse.json({ url: `/api/uploads/${key}` });