Touch interface for phones and tablets; category toolbar for mouse and touch

- touch.rs: gesture recognition (tap, double tap, long press, drag, two-finger pan/pinch/rotate)
- Touch mode: Auto (touch device or first touch) / On / Off in Settings -> Game
- Larger interface factor on touch screens, top bar wraps, smaller minimap, fewer messages
- Toolbar grouped into categories with pop-up rows and a menu button, also on the desktop
- Long press shows information or drops held units; double tap with the hand slaps
- Savegame name via the browser's text dialog when the name field is tapped
- Touch help texts (EN/DE)

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

README.md

@@ -56,7 +56,7 @@ The soundtrack consists of FastTracker 2 modules in `assets/music/`, generated b
 | Right drag, WASD, arrows, screen edge | Move the camera |
 | Middle drag, Q/E, R/F | Rotate / tilt the camera |
 | Mouse wheel | Zoom |
-| 1–9, 0, X, V | Select a tool or spell |
+| 1–9, 0, X, V, K, J, B, C, T | Select a tool or spell |
 | P / Space | Pause |
 | M, +/- | Sound on/off, volume |
 | G | Tile outlines on/off |
@@ -64,6 +64,22 @@ The soundtrack consists of FastTracker 2 modules in `assets/music/`, generated b
 
 All keys except Esc and the arrow keys can be changed in Settings → Keys.
 
+The toolbar groups the tools into categories (Dig, Hand, Rooms, Towers, Spells, Orders) plus a menu button; categories with several tools open a row above the toolbar. The keys select tools directly.
+
+### Touch (phones and tablets)
+
+The touch interface switches on automatically on touch devices or after the first touch (Settings → Game → Touch interface: Auto / On / Off). It uses a larger interface and these gestures:
+
+| Gesture | Action |
+|---|---|
+| Tap | Use the tool (hand: pick up a unit; spells, flag, towers: at that spot) |
+| Drag | Dig, rooms and sell: mark a rectangle; other tools: move the map |
+| Two fingers | Move the map, pinch to zoom, twist to rotate the camera |
+| Long press | Information about the spot; hand: drop the units there |
+| Double tap (hand) | Backhand own units / punch heroes on your ground |
+
+The savegame name is entered with the browser's text dialog when the name field is tapped.
+
 ## Savegames
 
 When the game is served together with the savegame service (`server/`, started by `docker compose`), *Save Game* and *Load Game* open a list of savegames stored on the server: save under a new name (type it into the name field), overwrite, load or delete (overwrite and delete ask for a second click). The list is shared by everybody who can reach the game - protect a public installation, for example with a password on the reverse proxy.