Fix linting errors across backend and frontend

Backend: auto-fix and format all ruff issues, manually fix B904/B023/
SIM117/B007/E741/F841 errors, suppress B008 (FastAPI Depends) and F821
(SQLAlchemy forward refs) in config. Frontend: allow constant exports,
disable React compiler-specific rules (set-state-in-effect,
preserve-manual-memoization).

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

backend/src/app/models/encounter.py

@@ -21,7 +21,9 @@ class Encounter(Base):
     current_pokemon_id: Mapped[int | None] = mapped_column(
         ForeignKey("pokemon.id"), index=True
     )
-    is_shiny: Mapped[bool] = mapped_column(Boolean, default=False, server_default=text("false"))
+    is_shiny: Mapped[bool] = mapped_column(
+        Boolean, default=False, server_default=text("false")
+    )
     caught_at: Mapped[datetime] = mapped_column(
         DateTime(timezone=True), server_default=func.now()
     )