feat: Introduce default profile sections and fields, updating schema with isSystem and isSearchableOnly properties.

prisma/schema.prisma

@@ -224,6 +224,7 @@ model ProfileSection {
   sortOrder   Int      @default(0)
   isActive    Boolean  @default(true)
   isGlobal    Boolean  @default(false) // If true, applies to ALL agent types
+  isSystem    Boolean  @default(false) // If true, section cannot be deleted (system default)
 
   // Timestamps
   createdAt   DateTime @default(now())
@@ -234,6 +235,7 @@ model ProfileSection {
   agentTypeSections   AgentTypeSection[]
 
   @@index([isActive])
+  @@index([isSystem])
   @@index([sortOrder])
   @@map("profile_sections")
 }
@@ -273,6 +275,7 @@ model ProfileField {
   sortOrder       Int       @default(0)
   isActive        Boolean   @default(true)
   isRequired      Boolean   @default(false)
+  isSearchableOnly Boolean  @default(false) // If true, shown in edit form & search, but hidden on public profile
 
   // Validation rules (JSON)
   validation      Json?     // { min, max, minLength, maxLength, pattern, etc. }