Polish: live OFA age warning, puppy sorting, responsive fixes, form hints

- HealthRecordForm shows a live amber warning under Test Date when the dog is
  under the OFA minimum certification age (submit-time block unchanged)
- LitterDetail puppies sortable by name / sex / birth date
- Responsive at 375px: DogDetail photos+info grid stacks, header wraps;
  puppy grid uses min(220px,100%); navbar wraps with scrollable icon row;
  calendar uses minmax(0,1fr) columns so cells shrink instead of overflowing
- LitterForm explains why sire/dam selects are locked when editing
- Add .claude/launch.json for the vite dev server

Verified in-browser at 375px and desktop: no horizontal overflow on any page.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.claude/launch.json

@@ -0,0 +1,12 @@
+{
+  "version": "0.0.1",
+  "configurations": [
+    {
+      "name": "client",
+      "runtimeExecutable": "npm",
+      "runtimeArgs": ["run", "dev"],
+      "cwd": "client",
+      "port": 5173
+    }
+  ]
+}