Add starter, gift, and fossil encounters to seed data

Define special encounter data (starters, gifts, fossils) in a new
special_encounters module and merge them into route seed JSON during
generation. Add new route locations to ROUTE_ORDER for cities that
previously had no wild encounters (Saffron City, Pewter City, etc.).
Show colored method badges in the EncounterModal UI for special
encounter types.

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

backend/src/app/seeds/fetch_pokeapi.py

@@ -15,6 +15,8 @@ import re
 import sys
 from pathlib import Path
 
+from app.seeds.special_encounters import SPECIAL_ENCOUNTERS
+
 REPO_ROOT = Path(__file__).parents[4]  # backend/src/app/seeds -> repo root
 POKEAPI_DIR = REPO_ROOT / "data" / "pokeapi" / "data" / "api" / "v2"
 DATA_DIR = Path(__file__).parent / "data"
@@ -461,6 +463,7 @@ ROUTE_ORDER: dict[str, list[str]] = {
         "Route 22",
         "Route 2",
         "Viridian Forest",
+        "Pewter City",
         "Route 3",
         "Mt Moon",
         "Route 4",
@@ -480,6 +483,8 @@ ROUTE_ORDER: dict[str, list[str]] = {
         "Route 8",
         "Route 7",
         "Celadon City",
+        "Saffron City",
+        "Lavender Town",
         "Route 16",
         "Route 17",
         "Route 18",
@@ -553,6 +558,7 @@ ROUTE_ORDER: dict[str, list[str]] = {
         "Ilex Forest",
         "National Park",
         "Route 35",
+        "Goldenrod City",
         "Route 36",
         "Route 37",
         "Ecruteak City",
@@ -589,6 +595,7 @@ ROUTE_ORDER: dict[str, list[str]] = {
         "Route 1",
         "Viridian City",
         "Viridian Forest",
+        "Pewter City",
         "Route 2",
         "Route 3",
         "Mt Moon",
@@ -637,6 +644,7 @@ ROUTE_ORDER: dict[str, list[str]] = {
         "Petalburg Woods",
         "Rusturf Tunnel",
         "Route 116",
+        "Rustboro City",
         "Route 105",
         "Route 106",
         "Dewford Town",
@@ -653,6 +661,7 @@ ROUTE_ORDER: dict[str, list[str]] = {
         "Route 112",
         "Fiery Path",
         "Jagged Pass",
+        "Lavaridge Town",
         "Route 113",
         "Route 114",
         "Meteor Falls",
@@ -813,6 +822,29 @@ def aggregate_encounters(raw_encounters: list[dict]) -> list[dict]:
     return sorted(result, key=lambda x: (-x["encounter_rate"], x["pokemon_name"]))
 
 
+def merge_special_encounters(routes: list[dict], special_data: dict[str, list[dict]]) -> list[dict]:
+    """Merge special encounters into existing routes or create new ones."""
+    # Build lookup: route name -> route dict (including children)
+    route_map: dict[str, dict] = {}
+    for r in routes:
+        route_map[r["name"]] = r
+        for child in r.get("children", []):
+            route_map[child["name"]] = child
+
+    for location_name, encounters in special_data.items():
+        for enc in encounters:
+            all_pokemon_dex.add(enc["national_dex"])
+
+        if location_name in route_map:
+            route_map[location_name]["encounters"].extend(encounters)
+        else:
+            new_route = {"name": location_name, "order": 0, "encounters": encounters}
+            routes.append(new_route)
+            route_map[location_name] = new_route
+
+    return routes
+
+
 def process_version(version_name: str, vg_info: dict, vg_key: str) -> list[dict]:
     """Process all locations for a specific game version.
 
@@ -911,6 +943,11 @@ def process_version(version_name: str, vg_info: dict, vg_key: str) -> list[dict]
                     "encounters": aggregated,
                 })
 
+    # Merge special encounters (starters, gifts, fossils)
+    special_data = SPECIAL_ENCOUNTERS.get(vg_key, {})
+    if special_data:
+        routes = merge_special_encounters(routes, special_data)
+
     # Sort routes by game progression order
     routes = sort_routes_by_progression(routes, vg_key)