Rivers and bridges: water and lava tiles, bridge tool, burning in lava

- New tile kinds (appended for the savegame codec): water, lava, wooden bridge, stone bridge, core shard
- Sunken river beds with banks, bridge decks with rails, lava glow and lights
- Bridge tool (key U, rooms category): bridges grow from own ground, 30 gold/tile over water, 75 over lava
- Selling a bridge drops the units on it into the river (water: swim to the bank, lava: burn)
- Cannon blasts and punches knock units back; into lava = burnt (heroes still pay their bounty)
- Heroes cannot path through rivers; texts EN/DE; tests for bridges and lava

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

lang/de.lang

@@ -145,7 +145,7 @@ help.k_slap = Shift+Links      Hand: Rückhand für eigene, Faust für Helden au
 help.k_pan = Rechts ziehen    Karte verschieben (auch WASD/Pfeile, Bildrand)
 help.k_rot = Mitte ziehen     Kamera drehen und neigen (auch Q/E, R/F)
 help.k_zoom = Mausrad          Zoomen
-help.k_tools = 1-9,0,X,V,K,J,B,C,T  Werkzeug
+help.k_tools = 1-9,0,X,V,K,J,B,C,T,U  Werkzeug
 help.k_misc = P / Leertaste    Pause      M  Ton an/aus   +/-  Lautstärke
 help.k_misc2 = G                Kachel-Umrisse an/aus     H  Diese Hilfe
 help.s1 = 1. Grabe zum Portal und lass es von Grubenwichten erobern.
@@ -383,3 +383,21 @@ help.t_long = Lange drücken: Infos zur Stelle; Hand: Einheiten dort absetzen
 help.t_double = Doppelt tippen mit der Hand: Rückhand für eigene, Faust für Helden auf eigenem Gebiet
 help.t_tools = Werkzeugleiste: Kategorien öffnen eine Reihe Werkzeuge; die Menütaste öffnet das Pausemenü
 help.start_touch = Tippen zum Starten
+
+# rivers and bridges
+tool.bridge.label = Brücke
+tool.bridge.name = Brücke bauen
+tool.bridge.desc = Baut eine Brücke über Wasser oder Lava. Ziehe von deinem Gebiet aus über den Fluss; die Brücke wächst Feld für Feld von deinem Reich aus.
+cost.bridge = {0} Gold/Feld über Wasser, {1} über Lava
+hint.bridge_where = Brücken müssen an deinem Gebiet beginnen: Ziehe von deinem Reich aus über den Fluss.
+hint.bridge_river = Brücken lassen sich nur über Wasser oder Lava bauen.
+msg.hero_burned = Ein {0} ist in die Lava gefallen! +{1} Gold.
+msg.creature_burned = Dein {0} ist in die Lava gefallen.
+tile.water = Unterirdischer Fluss
+tile.water_info = Niemand kann hindurchwaten. Baue eine Brücke.
+tile.lava = Lava
+tile.lava_info = Was hineinfällt, verbrennt. Steinbrücken führen hinüber.
+tile.bridge = Holzbrücke
+tile.lavabridge = Steinbrücke
+tile.shard = Splitter deines Seelenkerns
+tile.shard_info = Erobere diese Kammer, um den Splitter zurückzuholen.

lang/en.lang

@@ -146,7 +146,7 @@ help.k_slap = Shift+Left      Hand: backhand own units, punch heroes on your gro
 help.k_pan = Right drag      Move the map (also WASD/arrows, screen edge)
 help.k_rot = Middle drag     Rotate and tilt the camera (also Q/E, R/F)
 help.k_zoom = Mouse wheel     Zoom
-help.k_tools = 1-9,0,X,V,K,J,B,C,T  Select tool
+help.k_tools = 1-9,0,X,V,K,J,B,C,T,U  Select tool
 help.k_misc = P / Space       Pause      M  Sound on/off   +/-  Volume
 help.k_misc2 = G               Tile outlines on/off     H  This help
 help.s1 = 1. Dig to the portal and let your Pit Imps claim it.
@@ -384,3 +384,21 @@ help.t_long = Long press: information about the spot; hand: drop the units there
 help.t_double = Double tap with the hand: backhand own units, punch heroes on your ground
 help.t_tools = Toolbar: categories open a row of tools; the menu button opens the pause menu
 help.start_touch = Tap to start
+
+# rivers and bridges
+tool.bridge.label = Bridge
+tool.bridge.name = Build Bridge
+tool.bridge.desc = Builds a bridge over water or lava. Drag from your own ground across the river; the bridge grows tile by tile from your territory.
+cost.bridge = {0} gold/tile over water, {1} over lava
+hint.bridge_where = Bridges must start at your own ground: drag from your territory across the river.
+hint.bridge_river = Bridges can only be built over water or lava.
+msg.hero_burned = A {0} fell into the lava! +{1} gold.
+msg.creature_burned = Your {0} fell into the lava.
+tile.water = Underground river
+tile.water_info = Nobody can wade through it. Build a bridge.
+tile.lava = Lava
+tile.lava_info = Whatever falls in burns. Stone bridges cross it.
+tile.bridge = Wooden bridge
+tile.lavabridge = Stone bridge
+tile.shard = Shard of your soul core
+tile.shard_info = Claim this chamber to take the shard back.