Pin skills to the top of the sidebar

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

game.py

@@ -1033,7 +1033,7 @@ RAID_TRAITS = ["lightly armoured, heavy on archers", "mounted and fast, few bows
 
 # --- world ---------------------------------------------------------------
 
-WORLD_VERSION = 18
+WORLD_VERSION = 19
 
 
 def new_world(now: float, speed: float = 1.0) -> dict:
@@ -1183,6 +1183,10 @@ def migrate(world: dict, now: float | None = None) -> dict:
             for slot in ("ring", "amulet", "trinket"):
                 player["equip"].setdefault(slot, None)
         world["version"] = 18
+    if world["version"] < 19:
+        for player in world["players"].values():
+            player.setdefault("pinned", [])
+        world["version"] = 19
     return world
 
 
@@ -1425,6 +1429,7 @@ def new_player(uid: str, name: str, cls: str, now: float) -> dict:
         "perks": {"bank_slot": 0},
         "garrison": False,
         "donated": 0,
+        "pinned": [],  # skills pinned to the top of the sidebar
     }
 
 
@@ -3841,6 +3846,17 @@ def buy_perk(player: dict, perk: str) -> str | None:
     return None
 
 
+def toggle_pin(player: dict, skill: str) -> str | None:
+    if skill not in SKILL_IDS:
+        return "No such skill"
+    pinned = player["pinned"]
+    if skill in pinned:
+        pinned.remove(skill)
+    else:
+        pinned.append(skill)
+    return None
+
+
 # --- icons ------------------------------------------------------------------------
 # Every item, skill, class, building, prayer and output-less action gets a
 # game-icons.net glyph (CC BY 3.0) and a tint. Families share a shape and are