feat(storage): add S3 image storage support with file-based config and migration script

app/schemas.py

@@ -1,6 +1,6 @@
 from datetime import datetime
 
-from pydantic import BaseModel
+from pydantic import BaseModel, model_validator
 
 
 # ---------- Profile ----------
@@ -23,6 +23,13 @@ class ProfileOut(BaseModel):
 
     model_config = {"from_attributes": True}
 
+    @model_validator(mode="after")
+    def _resolve_image_urls(self) -> "PostcardOut":
+        from app.storage import resolve_url
+        self.image_front = resolve_url(self.image_front) or None
+        self.image_back = resolve_url(self.image_back) or None
+        return self
+
 
 # ---------- Postcard ----------
 
@@ -68,3 +75,10 @@ class PostcardOut(BaseModel):
     updated_at: datetime
 
     model_config = {"from_attributes": True}
+
+    @model_validator(mode="after")
+    def _resolve_image_urls(self) -> "PostcardOut":
+        from app.storage import resolve_url
+        self.image_front = resolve_url(self.image_front) or None
+        self.image_back = resolve_url(self.image_back) or None
+        return self