feat(health): health card share link, PDF export, weight chart in card

- ShareDialog: expiry selector (7/14/30/60/90 days, default 14), shows
  expiry date after generation, "Als PDF öffnen / drucken" button
- WeightChart extracted to standalone component (WeightChart.tsx) so it
  can be shared between HealthDashboard and the public health card page
- Health card page: renders WeightChart when 2+ weight entries exist
- AutoPrint client component: auto-triggers window.print() when card is
  opened with ?print=1 (600ms delay for render to settle)
- README: Phase 6 + Phase 7 marked complete with full feature summaries;
  project structure and router list updated

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/trpc/routers/health.ts

@@ -135,27 +135,43 @@ export const healthRouter = router({
   // ── Health Card ──────────────────────────────────────────────────────────────
 
   getOrCreateCard: protectedProcedure
-    .input(z.object({ petId: z.string().min(1) }))
+    .input(z.object({
+      petId: z.string().min(1),
+      expiryDays: z.union([
+        z.literal(7), z.literal(14), z.literal(30),
+        z.literal(60), z.literal(90),
+      ]).default(14),
+    }))
     .mutation(async ({ ctx, input }) => {
       await assertOwner(ctx.prisma, input.petId, ctx.userId);
+      const expiresAt = new Date();
+      expiresAt.setDate(expiresAt.getDate() + input.expiryDays);
       const card = await ctx.prisma.healthCard.upsert({
         where: { petId: input.petId },
-        update: {},
-        create: { petId: input.petId },
+        update: { expiresAt },
+        create: { petId: input.petId, expiresAt },
       });
-      return { token: card.token };
+      return { token: card.token, expiresAt: card.expiresAt };
     }),
 
   regenerateCard: protectedProcedure
-    .input(z.object({ petId: z.string().min(1) }))
+    .input(z.object({
+      petId: z.string().min(1),
+      expiryDays: z.union([
+        z.literal(7), z.literal(14), z.literal(30),
+        z.literal(60), z.literal(90),
+      ]).default(14),
+    }))
     .mutation(async ({ ctx, input }) => {
       await assertOwner(ctx.prisma, input.petId, ctx.userId);
       const newToken = crypto.randomUUID().replace(/-/g, "");
+      const expiresAt = new Date();
+      expiresAt.setDate(expiresAt.getDate() + input.expiryDays);
       const card = await ctx.prisma.healthCard.upsert({
         where: { petId: input.petId },
-        update: { token: newToken },
-        create: { petId: input.petId, token: newToken },
+        update: { token: newToken, expiresAt },
+        create: { petId: input.petId, token: newToken, expiresAt },
       });
-      return { token: card.token };
+      return { token: card.token, expiresAt: card.expiresAt };
     }),
 });