Use circular cards for people (#691)

## Description
Clips person images to a circle. The rectangle is still used in grid
pages like favorite people.

This PR also updates the fallback image to use a person icon if there is
no image for that person

Also adds role/job to discover pages' people rows

### Related issues
Closes #682 

### Screenshots

![Image](https://github.com/user-attachments/assets/9ca5c25b-5ba0-49d9-a680-6520804b0ace)

app/src/main/java/com/github/damontecres/wholphin/data/model/DiscoverItem.kt

@@ -184,7 +184,7 @@ data class DiscoverItem(
         id = credit.id!!,
         type = SeerrItemType.fromString(credit.mediaType, SeerrItemType.PERSON),
         title = credit.name ?: credit.title,
-        subtitle = null,
+        subtitle = credit.character,
         overview = credit.overview,
         availability =
             SeerrAvailability.from(credit.mediaInfo?.status)
@@ -199,7 +199,7 @@ data class DiscoverItem(
         id = credit.id!!,
         type = SeerrItemType.fromString(credit.mediaType, SeerrItemType.PERSON),
         title = credit.name ?: credit.title,
-        subtitle = null,
+        subtitle = credit.job,
         overview = credit.overview,
         availability =
             SeerrAvailability.from(credit.mediaInfo?.status)

app/src/main/java/com/github/damontecres/wholphin/data/model/Person.kt

@@ -1,5 +1,6 @@
 package com.github.damontecres.wholphin.data.model
 
+import androidx.compose.runtime.Stable
 import org.jellyfin.sdk.api.client.ApiClient
 import org.jellyfin.sdk.api.client.extensions.imageApi
 import org.jellyfin.sdk.model.UUID
@@ -7,6 +8,7 @@ import org.jellyfin.sdk.model.api.BaseItemPerson
 import org.jellyfin.sdk.model.api.ImageType
 import org.jellyfin.sdk.model.api.PersonKind
 
+@Stable
 data class Person(
     val id: UUID,
     val name: String?,