fix: Update fields to use Optional type for better clarity and handling of null values

app/config.py

@@ -5,7 +5,7 @@ from functools import lru_cache
 class Settings(BaseSettings):
     app_name: str = "Hadith Scholar API"
     app_version: str = "0.1.0"
-    debug: bool = False
+    debug: Optional[bool] = None
 
     # PostgreSQL
     pg_host: str = "pg.betelgeusebytes.io"

app/models/schemas.py

@@ -67,8 +67,8 @@ class TopicTag(BaseModel):
 class NarratorInChain(BaseModel):
     order: int = Field(description="Position in chain: 1=closest to compiler, last=closest to Prophet ﷺ")
     name_arabic: str = Field(description="Narrator's Arabic name as it appears in the hadith text")
-    name_transliterated: str = Field("", description="Latin transliteration of the name")
+    name_transliterated: Optional[str] = Field(None, description="Latin transliteration of the name")
-    entity_type: str = Field("", description="PERSON, KUNYA (أبو/أم), NISBA (attributional), or TITLE (رسول الله)")
+    entity_type: Optional[str] = Field(None, description="PERSON, KUNYA (أبو/أم), NISBA (attributional), or TITLE (رسول الله)")
     transmission_verb: Optional[str] = Field(None, description="Exact Arabic transmission verb: حدثنا، أخبرنا، عن، سمعت")
 
     model_config = {
@@ -121,8 +121,8 @@ class HadithDetail(BaseModel):
 
 class NarratorSummary(BaseModel):
     name_arabic: str = Field(description="Primary Arabic name")
-    name_transliterated: str = Field("", description="Latin transliteration")
+    name_transliterated: Optional[str] = Field(None, description="Latin transliteration")
-    entity_type: str = Field("", description="PERSON, KUNYA, NISBA, TITLE")
+    entity_type: Optional[str] = Field(None, description="PERSON, KUNYA, NISBA, TITLE")
     generation: Optional[str] = Field(None, description="طبقة: صحابي، تابعي، تابع التابعين")
     reliability_grade: Optional[str] = Field(None, description="جرح وتعديل: ثقة، صدوق، ضعيف، متروك")
     hadith_count: int = Field(0, description="Number of hadiths this narrator appears in")
@@ -166,8 +166,8 @@ class PlaceRelation(BaseModel):
 
 class NarratorProfile(BaseModel):
     name_arabic: str = Field(description="Primary Arabic name")
-    name_transliterated: str = Field("", description="Latin transliteration")
+    name_transliterated: Optional[str] = Field(None, description="Latin transliteration")
-    entity_type: str = Field("", description="PERSON, KUNYA, NISBA, TITLE")
+    entity_type: Optional[str] = Field(None, description="PERSON, KUNYA, NISBA, TITLE")
     full_nasab: Optional[str] = Field(None, description="Full lineage: فلان بن فلان بن فلان")
     kunya: Optional[str] = Field(None, description="أبو/أم name (e.g. أبو هريرة)")
     nisba: Optional[str] = Field(None, description="Attributional name (e.g. البخاري، المدني، الزهري)")
@@ -226,8 +226,8 @@ class NarratorProfile(BaseModel):
 
 class IsnadNode(BaseModel):
     name_arabic: str = Field(description="Narrator Arabic name")
-    name_transliterated: str = Field("", description="Latin transliteration")
+    name_transliterated: Optional[str] = Field(None, description="Latin transliteration")
-    entity_type: str = Field("", description="PERSON, KUNYA, NISBA, TITLE")
+    entity_type: Optional[str] = Field(None, description="PERSON, KUNYA, NISBA, TITLE")
     generation: Optional[str] = Field(None, description="طبقة")
     reliability_grade: Optional[str] = Field(None, description="جرح وتعديل grade")
 
@@ -271,9 +271,9 @@ class IsnadChain(BaseModel):
 
 class NarratorInteraction(BaseModel):
     narrator_a: str = Field(description="First narrator Arabic name")
-    narrator_a_transliterated: str = Field("", description="First narrator transliteration")
+    narrator_a_transliterated: Optional[str] = Field(None, description="First narrator transliteration")
     narrator_b: str = Field(description="Second narrator Arabic name")
-    narrator_b_transliterated: str = Field("", description="Second narrator transliteration")
+    narrator_b_transliterated: Optional[str] = Field(None, description="Second narrator transliteration")
     relationship_type: str = Field(description="NARRATED_FROM, TEACHER_OF, HEARD_BY, STUDENT_OF")
     shared_hadith_count: int = Field(0, description="Number of hadiths connecting them")
     hadith_ids: list[str] = Field(default_factory=list, description="IDs of connecting hadiths (max 20)")
@@ -295,7 +295,7 @@ class NarratorInteraction(BaseModel):
 
 class NarratorConnection(BaseModel):
     narrator: str = Field(description="Connected narrator Arabic name")
-    narrator_transliterated: str = Field("", description="Transliteration")
+    narrator_transliterated: Optional[str] = Field(None, description="Transliteration")
     connection_type: str = Field(description="Relationship type")
     direction: str = Field(description="'incoming' (they → this) or 'outgoing' (this → them)")
 
@@ -311,7 +311,7 @@ class NarratorNetwork(BaseModel):
 class SemanticSearchResult(BaseModel):
     hadith: HadithSummary = Field(description="Matching hadith")
     score: float = Field(description="Cosine similarity score (0-1, higher = more relevant)")
-    collection: str = Field("", description="Collection name")
+    collection: Optional[str] = Field(None, description="Collection name")
 
     model_config = {
         "json_schema_extra": {