Implement unit action queueing and busy state validation

config/game.yaml

@@ -1,5 +1,11 @@
 movement_tick_duration: 30.0
 
+# Action queue configuration
+action_queue:
+  max_size: 5
+  auto_queue_move_when_busy: true
+  allow_action_queueing: true
+
 # Camera settings
 camera:
   min_zoom: 2.0

config/strings_en.yaml

@@ -45,6 +45,27 @@ ui:
 
   unit:
     moving: "Moving"
+    move_queued: "Movement queued"
+    queue_cleared: "Queued actions cancelled"
+    queue_full: "Action queue full!"
+    action_queued: "Action queued: %1"
+    action_cancelled: "%1 cancelled"
+    farm_queued: "Build Farm queued on arrival"
+    farm_started: "Constructing Farm..."
+    farm_completed: "Farm completed!"
+    farm_completed_consumed: "Farm completed! (Builder consumed)"
+    farm_completed_charges: "Farm completed! (%1 %2 remaining)"
+    city_queued: "Found City queued on arrival"
+    city_founded: "%1 founded!"
+    already_building: "Already busy building!"
+    busy: "Unit is busy!"
+    cannot_act_busy: "Unit cannot perform action while busy!"
+    tile_occupied: "Tile already has an improvement!"
+    cannot_build_here: "Cannot build here! Allowed on: %1"
+    cannot_build_destination: "Cannot build on destination terrain! Allowed on: %1"
+    no_build_charges: "No build charges remaining!"
+    charge_singular: "charge"
+    charge_plural: "charges"
     impassable_terrain: "Impassable terrain!"
     naval_only_water: "Ships can only sail on water!"
     no_path: "No reachable path!"
@@ -53,6 +74,26 @@ ui:
     defeated: "Defeated!"
     city_already_here: "A city already exists here!"
     unsuitable_terrain: "Unsuitable terrain!"
+    civilian_unit: "Civilian unit"
+    military_unit: "Military unit"
+    speed_format: "Speed: %1 hex/tick"
+    cost_format: "Cost: %1 pts"
+    combat_format: "Attack: %1 | Range: %2 hex"
+    building_pct: "Building... %1%"
+    charges_format: "Charges: %1"
+    status_queued: "Queued: %1"
+    btn_move: "Move [M]"
+    btn_attack: "Attack [A]"
+    btn_build_city: "Settle [B]"
+    btn_build_farm: "Farm [F]"
+    btn_farm_queued: "Farm (Queued)"
+    btn_farm_building: "Building %1%"
+    tip_move: "Move (M)"
+    tip_attack: "Attack (A) [Range: %1]"
+    tip_build_city: "Found City (B)"
+    tip_build_farm: "Build Farm (F)"
+    tip_farm_building: "Busy building... %1%"
+    tip_farm_queued: "Build Farm (Queued on arrival - click to cancel)"
 
   city:
     center: "City Center"