Enforce Dupes Clause and Shiny Clause rules

Dupes Clause greys out Pokemon in the encounter modal whose evolution
family has already been caught, preventing duplicate selections. Shiny
Clause adds a dedicated Shiny Box and lets shiny catches bypass the
one-per-route lock via a new is_shiny column on encounters and a
/pokemon/families endpoint that computes evolution family groups.

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

backend/src/app/schemas/encounter.py

@@ -11,6 +11,7 @@ class EncounterCreate(CamelModel):
     nickname: str | None = None
     status: str
     catch_level: int | None = None
+    is_shiny: bool = False
 
 
 class EncounterUpdate(CamelModel):
@@ -32,6 +33,7 @@ class EncounterResponse(CamelModel):
     catch_level: int | None
     faint_level: int | None
     death_cause: str | None
+    is_shiny: bool
     caught_at: datetime