Add encounter condition support with rate display

Add a `condition` column to RouteEncounter for time-of-day, weather,
and season variants. Seed loader expands `conditions` dict into
per-condition rows. EncounterModal shows condition filter tabs with
per-condition encounter rates, and displays rates for all standard
encounter methods (walk, surf, fishing, etc.).

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

backend/src/app/schemas/pokemon.py

@@ -42,6 +42,7 @@ class RouteEncounterResponse(CamelModel):
     game_id: int
     encounter_method: str
     encounter_rate: int
+    condition: str = ""
     min_level: int
     max_level: int
 
@@ -55,6 +56,7 @@ class PokemonEncounterLocationItem(CamelModel):
     route_name: str
     encounter_method: str
     encounter_rate: int
+    condition: str = ""
     min_level: int
     max_level: int
 
@@ -89,6 +91,7 @@ class RouteEncounterCreate(CamelModel):
     game_id: int
     encounter_method: str
     encounter_rate: int
+    condition: str = ""
     min_level: int
     max_level: int
 
@@ -96,6 +99,7 @@ class RouteEncounterCreate(CamelModel):
 class RouteEncounterUpdate(CamelModel):
     encounter_method: str | None = None
     encounter_rate: int | None = None
+    condition: str | None = None
     min_level: int | None = None
     max_level: int | None = None
 
@@ -178,6 +182,7 @@ class BulkRouteEncounterItem(BaseModel):
     pokeapi_id: int
     method: str
     encounter_rate: int
+    condition: str = ""
     min_level: int
     max_level: int