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/api/pokemon.py

@@ -12,6 +12,7 @@ from app.schemas.pokemon import (
     BulkImportItem,
     BulkImportResult,
     EvolutionResponse,
+    FamiliesResponse,
     PaginatedPokemonResponse,
     PokemonCreate,
     PokemonResponse,
@@ -109,6 +110,44 @@ async def create_pokemon(
     return pokemon
 
 
+@router.get("/pokemon/families", response_model=FamiliesResponse)
+async def get_pokemon_families(
+    session: AsyncSession = Depends(get_session),
+):
+    """Return evolution families as connected components of Pokemon IDs."""
+    from collections import deque
+
+    result = await session.execute(select(Evolution))
+    evolutions = result.scalars().all()
+
+    # Build undirected adjacency list
+    adj: dict[int, set[int]] = {}
+    for evo in evolutions:
+        adj.setdefault(evo.from_pokemon_id, set()).add(evo.to_pokemon_id)
+        adj.setdefault(evo.to_pokemon_id, set()).add(evo.from_pokemon_id)
+
+    # BFS to find connected components
+    visited: set[int] = set()
+    families: list[list[int]] = []
+    for node in adj:
+        if node in visited:
+            continue
+        component: list[int] = []
+        queue = deque([node])
+        while queue:
+            current = queue.popleft()
+            if current in visited:
+                continue
+            visited.add(current)
+            component.append(current)
+            for neighbor in adj.get(current, set()):
+                if neighbor not in visited:
+                    queue.append(neighbor)
+        families.append(sorted(component))
+
+    return FamiliesResponse(families=families)
+
+
 @router.get("/pokemon/{pokemon_id}", response_model=PokemonResponse)
 async def get_pokemon(
     pokemon_id: int, session: AsyncSession = Depends(get_session)