feat(persons): add notes field to person profile (issue #23)

V5 Flyway migration adds TEXT notes column; Person entity, service, and
controller updated to persist notes. Frontend edit form adds textarea and
view mode renders the notes section. Backed by 2 new service unit tests
(persist + blank clears).

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

frontend/src/routes/persons/[id]/+page.svelte

@@ -86,6 +86,16 @@
                                     class="block w-full border border-gray-300 rounded px-3 py-2 font-serif text-brand-navy focus:outline-none focus:border-brand-navy"
                                 />
                             </div>
+                            <div class="md:col-span-2">
+                                <label for="notes" class="block text-xs font-bold uppercase tracking-widest text-gray-400 mb-1">{m.person_label_notes()}</label>
+                                <textarea
+                                    id="notes"
+                                    name="notes"
+                                    rows="4"
+                                    placeholder={m.person_placeholder_notes()}
+                                    class="block w-full border border-gray-300 rounded px-3 py-2 font-serif text-brand-navy focus:outline-none focus:border-brand-navy resize-y"
+                                >{person.notes ?? ''}</textarea>
+                            </div>
                         </div>
 
                         <div class="flex gap-3">
@@ -136,6 +146,13 @@
                                 <span class="block text-lg font-serif text-brand-navy italic">"{person.alias}"</span>
                             </div>
                             {/if}
+
+                            {#if person.notes}
+                            <div class="md:col-span-2">
+                                <span class="block text-xs font-bold font-sans text-gray-400 uppercase tracking-widest mb-1">{m.person_label_notes()}</span>
+                                <p class="text-base font-serif text-brand-navy whitespace-pre-wrap">{person.notes}</p>
+                            </div>
+                            {/if}
                         </div>
                     </div>
                 </div>